# Mathematics Grade 12 Paper 1 KwaZulu Natal Mock 2019 Memo

> Grade 12 Mathematics Paper 1 memorandum from the KwaZulu Natal Mock Exam 2019, 13 pages. Read online or download the free PDF.

- Page: https://www.hlayiso.com/library/2019-grade-12-math-trial-exam-paper-1-kzn-memo/b2cc6d50-0058-4148-ac74-94f5bb846502
- Updated: 2026-09-27
- Subject: Mathematics
- Grade: Grade 12
- Document type: Memorandum
- Year: 2019
- Exam period: KwaZulu Natal Mock Exam
- Paper: 1
- Curriculum: CAPS
- Pages: 13

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### Page 1

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                                 MATHEMATICS P1

                                  SEPTEMBER 2019
                        PREPARATORY EXAMINATION
                              MARKING GUIDELINE

                                  NATIONAL
                             SENIOR CERTIFICATE

                                     GRADE 12

 MARKS: 150

 TIME: 3 hours

                       This marking guideline consists of 13 pages.

Copyright Reserved                                                    Please Turn Over

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Mathematics P1                                        2                         September 2019 Preparatory Examination
                                                       NSC Marking Guideline
QUESTION 1
 1.1.1 𝑥 = 0 𝑜𝑟 𝑥 = 4                                             A✓ 0 A✓ 4                                 (2)
 1.1.2    2 x2 + 5x − 1 = 0                                       A✓standard form
                               − b  b 2 − 4ac
                       x=
                                     2a
                             − (5)  (5) 2 − 4(2)(−1)
                           =                                      CA✓substitution in correct formula
                                      2(2)
                           = 0,19    or      − 2,69               CA✓CA✓answers                             (4)
                                                                  (penalize 1 mark if rounding off is
                                                                  incorrect-once here for entire paper)
 1.2.1   √𝑥 − 2 = 2 − 𝑥

         (√𝑥 − 2)2 = (2 − 𝑥)2                                     A✓ squaring both sides
         𝑥 − 2 = 4 − 4𝑥 + 𝑥 2                                     CA✓standard form
         𝑥 2 − 5𝑥 + 6 = 0                                         CA✓factors
         (𝑥 − 2)(𝑥 − 3) = 0                                       CA✓answers and rejecting                  (4)
         𝑥 = 2 𝑜𝑟 𝑥 = 3
                    n/a
                                                                  OR
         OR

         √𝑥 − 2 = 2 − 𝑥                                           A✓ A✓each inequality
         𝑥 − 2 ≥ 0 𝑎𝑛𝑑 2 − 𝑥 ≥ 0                                  A✓both inequalities                       (4)
         𝑥 ≥ 2 𝑎𝑛𝑑 𝑥 ≤ 2                                          CA✓answer
         𝑥=2                                                      Answer only FULL MARKS
 1.2.2   𝑝2 − 𝑝 = 𝑥                                               letting 𝑝2 − 𝑝 = 𝑥
         ∴ 𝑝2 − 𝑝 = 2                                             CA✓𝑝2 − 𝑝 = 2
         𝑝2 − 𝑝 − 2 = 0                                           CA✓standard form
         (𝑝 + 1)(𝑝 − 2) = 0                                       CA✓factors
         𝑝 = −1 𝑜𝑟 𝑝 = 2                                          CA✓answers
                                                                  MAX 3marks if four solutions              (4)
                                                                  arrived at
 1.3     −2𝑥 2 + 5𝑥 ≤ 0
                5
         2𝑥 (𝑥 − ) ≥ 0                                            AA✓✓ factors
                2
                                    5                                                              5
         𝑥≤0         or        𝑥≥                                 CA✓ 𝑥 ≤ 0          CA✓ 𝑥 ≥ 2              (4)
                                    2
         OR
                                                      +           OR

           +           +
                                                                  If graphical Solution is used:
           0         2,5                OR        0       2,5     AA 2 marks for graph
                                                 -          -     CACA 2 marks for answer
                 -                                                                                          (4)

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Mathematics P1                                   3                        September 2019 Preparatory Examination
                                                  NSC Marking Guideline
 1.4     2𝑥+1 + 2𝑥 = 3𝑦+2 − 3𝑦
         2𝑥 (2 + 1) = 3𝑦 (9 − 1)                             A✓factorising
         2𝑥 (3) = 3𝑦 (8)                                     CA✓simplifying
         2𝑥−3 = 3𝑦−1                                         CA✓exponential form
         𝑥 − 3 = 0 𝑎𝑛𝑑 𝑦 − 1 = 0                             CA✓each exponent and equal to 0
         𝑥 = 3 𝑎𝑛𝑑 𝑦 = 1                                     CA✓x and y value
         𝑥+𝑦 =4                                              CA✓answer                                (6)
                                                             If 𝑥 − 3 = 0 𝑎𝑛𝑑 𝑦 − 1 = 0 is
                                                             missing then maximum 5/6 marks
                                                                                                     [24]
QUESTION 2
 2.1     48 ;    63                                          A✓answers                                (1)
 2.2             8         15          24          35

          1D          7            9        11

          2D               2           2
                                                             A✓a value
         2𝑎 = 2          𝑎=1                                 CA✓b value
         3𝑎 + 𝑏 = 7      𝑏=4
         𝑎+𝑏+𝑐 =8        𝑐=3                                 CA✓c value
               2
         𝑇𝑛 = 𝑛 + 4𝑛 + 3                                     CA✓answer                                (4)
         OR                                                  OR
         2𝑎 = 2           𝑎=1                                A✓a value
         𝑇1 + 𝑑2 − 𝑑1 = 𝑐
         8+2−7= 𝑐
         3=c                                                 CA✓c value
         𝑇𝑛 = 𝑛2 + 𝑏𝑛 + 3
         8= 1+𝑏+3
         𝑏=4                                                 CA✓b value                               (4)
         𝑇𝑛 = 𝑛2 + 4𝑛 + 3                                    CA✓answer

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Mathematics P1                                     4                        September 2019 Preparatory Examination
                                                    NSC Marking Guideline
         OR                                                    OR
                               (n − 1(n − 2)                   A✓formula
         Tn = T1 + (n − 1)d1 +               d2
                                     2                         A✓substitution into correct formula
                               (n − 1(n − 2)
            = 8 + (n − 1)(7) +               (2)
                                     2
            = 8 + 7n − 7 + n 2 − 3n + 2                        CA✓simplifying
            = n 2 + 4n + 3                                     CA✓answer                                (4)

         OR                                                    OR
                                                               A✓formula
              n −1
         Tn =       2a + (n − 2)d  + T1
                2
              n −1                                             A✓substitution into correct formula
            =       2(7) + (n − 2)(2) + 8
                2
                                                               CA✓simplifying
              n −1
            =       14 + 2n − 4 + 8
                2                                                                                      (4)
              n −1
            =       2n + 10 + 8
                2
            = (n − 1)(n + 5) + 8
            = n 2 + 4n − 5 + 8                                 CA✓answer
            = n + 4n + 3
                  2

                                                                                                        [5]

QUESTION 3
 3.1     T2 − T1 = T3 − T2                                     A✓ equating differences
         𝑝 + 5 − 2𝑝 + 3 = 2𝑝 + 7 − 𝑝 − 5
                                                               CA✓simplifying
         −𝑝 + 8 = 𝑝 + 2                                        CA✓answer
                                                                                                        (3)
         𝑝=3
 3.2     Pattern is 3 ; 8 ; 13 ; . ..

           Sn =
                 n
                   2a + (n − 1)d 
                 2                                             CA✓a = 3 and d = 5
          S120 =
                 120
                     2(3) + 119(5)                           CA✓substitution into formula
                  2
               = 36060                                         CA✓answer                                (3)
 3.3.1   x = k + 1 and y = k + 2                               A✓x – value A✓y – value                  (2)

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Mathematics P1                        5                             September 2019 Preparatory Examination
                                       NSC Marking Guideline
 3.3.2   𝑇𝑥 = 𝑎 + (𝑥 − 1)𝑑 = 3 + 5𝑘               CA✓substitution into nth term
         𝑇𝑦 = 𝑎 + (𝑘 + 1)𝑑                        CA✓3 + 5𝑘
         = 3 + (𝑘 + 1)(5)
         = 8 + 5𝑘                                 CA✓8+5𝑘
         𝑇𝑥 + 𝑇𝑦 = 11 + 10𝑘                       CA✓answer                                     (4)

                                                                                               [12]

QUESTION 4

 4.1.1   15 ; 5                                   AA✓✓both terms                                (2)
 4.1.2           a
          S =
               1− r
                15                                CA✓substitution of common ratio
             =
                   1
               1−
                   3
                                                  CA✓answer
               45
             =     = 22,5                                                                       (2)
                2
 4.2                             3
         𝑠𝑖𝑛 3 0∘ ; 𝑐𝑜𝑠 3 0∘ ;
                                 2
         1 √3 3
           ;     ;                                A✓listing terms
         2 2 2
              1
         𝑎 = ; 𝑟 = √3
              2
         𝑎𝑟 𝑛−1 = 40,5√3
         1      𝑛−1    81                               1          𝑛−1       81
           (√3)     =     √3                      CA✓2 (√3)              =      √3
                                                                             2
         2              2                                   𝑛−1          1
          𝑛−1        1
                                                  CA✓3 2 = 34 . 32
         3 2 = 34 . 32
         𝑛−1        1 9
                =4 =                                    𝑛−1          1       9
           2        2 2                           CA✓             = 42 = 2
         𝑛−1=9                                              2

               𝑛 = 10
                                                  CA✓answer                                     (5)
         OR                                       OR

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Mathematics P1                             6                         September 2019 Preparatory Examination
                                            NSC Marking Guideline
                                   3
         𝑠𝑖𝑛 3 0∘ ; 𝑐𝑜𝑠 3 0∘ ;
                                   2
         1 √3 3                                        A✓listing terms
           ;     ;
         2 2 2
              1
         𝑎 = ; 𝑟 = √3
              2
            𝑛−1
                   81
         𝑎𝑟     =     √3
                    2
         1      𝑛−1    81                                    1      𝑛−1       81
           (√3)      =    √3                           CA✓2 (√3)          =
                                                                              2
                                                                                 √3
         2              2
                      𝑛
            (√3)
                          = 81√3
                 √3
                          𝑛
         243= (√3)                                                        𝑛
                                                       CA✓243= (√3)
                      1                                              1
         35 = 32𝑛                                      CA✓ 35 = 32𝑛                            (5)

         n = 10                                        CA✓answer

                                                                                                 [9]

QUESTION 5

 5.1     𝑥 = 2 𝑎𝑛𝑑 𝑦 = −1                              AA✓𝑥 = 2 ✓𝑦 = −1                          (2)
 5.2     𝑦 − intercept :(0 ; −3)                       A✓y – intercept
                          −4
         𝑥 − intercept:        −1=0                         −4
                        2−𝑥                            A✓         −1=0
          −4     1                                          2−𝑥
               =
         2−𝑥 1
         −4 = 2 − 𝑥
         𝑥=6                                           A✓x – intercept
                                                                                                 (3)
         (6 ; 0)                                       (co-ordinate form not needed)

 5.3                          y                        CA✓x -intercepts
                                       f               CA✓y - intercept
                                                       CA✓both asymptotes

                              O                  x     A✓shape
                                   2       6                                                     (4)
                              -1

                              -3

                                                                                                 [9]

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Mathematics P1                           7                         September 2019 Preparatory Examination
                                          NSC Marking Guideline
QUESTION 6
 6.1     A(0; 6)                                     A✓answer (Must be in coordinate           (1)
                                                     form)
 6.2              𝑏                                  Using axis of symmetry                    (2)
         𝑥=−        = 2,5
                2𝑎
         S(5 ; 6)                                    A✓x – value A✓y – value

         OR                                          OR

         𝑦 =𝑥+1=6                                    A✓equating equation to 6                  (2)
         𝑥=5                                         A✓x – value
         𝑆(5 ; 6)
         OR                                          OR
                                                     A✓equating equation to 6
         𝑦 = −𝑥 2 + 5𝑥 + 6 = 6
         𝑥 2 − 5𝑥 = 0
         𝑥(𝑥 − 5) = 0                                                                          (2)
         𝑥 = 0 𝑜𝑟 𝑥 = 5
         𝑛/𝑎                                         A✓x – values and rejection
         𝑆(5 ; 6)
         OR
         −𝑥 2 + 5𝑥 + 6 = 𝑥 + 1
         ……………..
 6.3     −𝑥 2 + 5𝑥 + 6 = 0
         𝑥 2 − 5𝑥 − 6 = 0
         (𝑥 + 1)(𝑥 − 6) = 0
                                                     A✓factors
         𝑥 = −1 𝑜𝑟 𝑥 = 6                                                                       (3)
                                                     CACA✓✓x – values
         B(−1; 0), C(6; 0)
 6.4     (−𝑥 2 + 5𝑥 + 6) − (𝑥 + 1) = 5               A✓subtraction of both graphs
         −𝑥 2 + 5𝑥 + 6 − 𝑥 − 1 = 5
                                                     A✓equating to 5
         𝑥 2 − 4𝑥 = 0
         𝑥(𝑥 − 4) = 0                                CA✓factors
         𝑥 = 0 𝑜𝑟 4
                                                                                               (4)
         OR = 4units                                 CA✓OR value
 6.5.1           −1+6    5                           A✓midpoint formula
         𝑥=             =2
                  2
                                                     CA✓Axis of symmetry value
                     5 2  5        49
             𝑦 = −( ) + 5( ) + 6 =    = 12,25        CA✓substitution
                     2    2         4
              5
             ( ; 12,25)                              CA✓answer                                 (4)
              2
                                                     OR
         OR

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Mathematics P1                              8                        September 2019 Preparatory Examination
                                             NSC Marking Guideline
                  𝑏      5       5                      A✓formula
          𝑥 = − 2𝑎 = − 2(−1) = 2
                                                        CA✓Axis of symmetry value
                     5 2  5        49
             𝑦 = −( ) + 5( ) + 6 =    = 12,25           CA✓substitution
                     2    2         4
              5
             ( ; 12,25)                                 CA✓answer                                (4)
              2
         OR
                                                        OR
                                        5               A✓derivative and equal to 0
         𝑓 ′ (𝑥) = −2𝑥 + 5 = 0       ∴𝑥=2
                     5 2  5        49                   CA✓Axis of symmetry value
             𝑦 = −( ) + 5( ) + 6 =    = 12,25
                     2    2         4                   CA✓substitution
              5
             ( ; 12,25)                                                                          (4)
              2                                         CA✓answer
 6.5.2   PQ = −𝑥 2 + 4𝑥 + 5                             A✓ PQ in terms of x
                  𝑏      4
                                                        CA✓ substitution
          𝑥 = − 2𝑎 = − 2(−1) = 2                        CA✓x – value

         Max. PQ = −(2)2 + 4(2) + 5 = 9units            CA✓answer

                                                                                                 (4)
         OR                                             OR

         PQ = −𝑥 2 + 4𝑥 + 5                             A✓PQ in terms of x
                                                        CA✓derivative and equal to 0
         PQ′ = −2𝑥 + 4 = 0 ∴ 𝑥 = 2
                                                        CA✓x – value
                                                                                                (4)
         Max. PQ = −(2)2 + 4(2) + 5 = 9units            CA✓answer

                                                                                                [18]

QUESTION 7
 7.1     𝑦 = 5𝑥                                         AA✓✓ answer                              (2)
 7.2     𝑦 > 0 or 𝑦 ∈ (0 ; ∞)                           A✓answer                                 (1)
 7.3     𝑙𝑜𝑔5 𝑥 = −4                                    A✓Equating log graph to ─4
                    1
         𝑥 = 5−4 =                                      A✓writing in exponential form
                   625
                  1                                     CA✓end points
         0<𝑥≤
                 625                                    A✓ interval
                                                        Can be solved by log inequalities.       (4)

                                                                                                 [7]

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Mathematics P1                                          9                        September 2019 Preparatory Examination
                                                         NSC Marking Guideline
QUESTION 8
 8.1     𝐴 = 𝑃(1 − 𝑖)𝑛
         250000 = 𝑃(1 − 13,5%)5                                     A✓substitution into the correct
                250000                                              formula
         𝑃=
             (1 − 13,5%)5                                           CA✓making P the subject
         = 𝑅516249
                                                                    CA✓answer                                (3)
 8.2.1      𝑥[1 − (1 + 𝑖)−𝑛 ]                                       A✓value of n
         𝑃=
                   𝑖                                                A✓value of i
                                      14,25% −240                   CA✓substitution into correct
                       𝑥 [1 − (1 +             )    ]
                                        12                          formula
         950000 =                  14,25%
                                     12                                                                      (4)
         𝑥 = 𝑅11986,33                                              CA✓answer

 8.2.2           𝑥[1 − (1 + 𝑖)−𝑛 ]
         𝑃=
                        𝑖                                           A✓Present value formula
                                     14,25% −140                    A✓value of n
             11986,33 [1 − (1 +                )   ]
                                          12                        CA✓substitution into correct
         =                  14,25%
                                                                    formula
                              12
         = 𝑅816048,67                                               CA✓answer
                                                                                                             (4)
         OR                                                         OR
         𝐴 = 𝑃(1 + 𝑖)𝑛
                               14,25% 100
         𝐴 = 950 000 (1 +            )
                                 12                                 A✓Substitution into Compound
          =R3093215,766                                             Interest Formula
            𝑥[(1 + 𝑖)𝑛 − 1]
         𝐹=
                   𝑖
                             14,25% 100
            11986,33 [(1 + 12 ) − 1]                                CA✓substitution into Future Value
         𝐹=              14,25%                                     Formula
                                12

             =R2277167,107
         Balance on Loan
         = R3093215,766 −R2277167,107                               CA✓A -F                                  (4)
         = R816048,67                                               CA✓answer

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Mathematics P1                                             10                       September 2019 Preparatory Examination
                                                            NSC Marking Guideline
 8.2.3    A = P(1 + i) n
                                               4
                         14,25% 
            = 816 048,671 +                                          CA✓substitution
                            12 
            = R855 506,92

                           𝑥[1−(1+𝑖)−𝑛 ]
         855 506,92 =                                                  CA✓substitution of P and i
                                 𝑖
                                                                       A✓value of n
                                        14,25% −136
                        𝑥 [1 − (1 +                )   ]
                                          12
                    =                14,25%
                                      12                               CA✓answer
                    𝑥 = 𝑅12711,51                                                                               (4)

                                                                                                               [15]

QUESTION 9(penalize 1 mark once for incorrect notation in this question)
 9.1                   f (x + h ) − f (x )                       A✓formula
       f ( x) = lim
                 h →0          h

                      (x + h )2 − 1 ( x + h) −  x 2 − 1 x    A✓substitution
               = lim
                                   2                   2 
                 h →0                    h
                                           1     1             1
                      x 2 + 2 xh + h 2 − x − h − x 2 + x CA✓ simplification of numerator
               = lim                       2     2             2
                 h →0                       h                                                                   (5)
                                   1
                      h 2 x + h −                              CA✓factorization
               = lim 
                                     2
                 h →0         h
                       1
               = 2x −                                            CA✓answer
                       2                                         OR
      OR
                                     1
      𝑓(𝑥 + ℎ) = (𝑥 + ℎ)2 − (𝑥 + ℎ)
                                     2                           A✓value of f(x+h)
                                              1       1          CA✓ simplification
      𝑓(𝑥 + ℎ) = 𝑥 2 + 2𝑥ℎ + ℎ2 − 𝑥 − ℎ
                                              2       2
                                                1
      𝑓(𝑥 + ℎ) − 𝑓(𝑥) = 2𝑥ℎ + ℎ2 − ℎ
                                                2
                                            2   1                                                               (5)
      𝑓(𝑥 + ℎ) − 𝑓(𝑥) 2𝑥ℎ + ℎ − 2 ℎ
                             =
                ℎ                         ℎ
                                                1                CA✓factorization
      𝑓(𝑥 + ℎ) − 𝑓(𝑥) ℎ(2𝑥 + ℎ − 2)
                             =
                ℎ                        ℎ
                                     1                           A✓formula
      𝑓 ′ (𝑥) = lim (2𝑥 + ℎ − )
                  ℎ→0                2
                         1                                       CA✓answer
      𝑓 ′ (𝑥) = 2𝑥 −
                         2

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Mathematics P1                           11                       September 2019 Preparatory Examination
                                          NSC Marking Guideline
 9.2.1   𝑑         5
            [3𝑥4 + √𝑥 + 𝑎2 ]
         𝑑𝑥
         𝑑          1
            [3𝑥4 + 𝑥5 + 𝑎2 ]                         A✓rewriting in exponential form
         𝑑𝑥
                                                     A✓CA✓derivatives
                  1 4                                Penalize 1 mark if a is included in      (3)
         = 12𝑥 3 + 𝑥 −5
                  5                                  answer

 9.2.2   𝑥𝑦 = 𝑥 + 𝑥 2 − 1                            A✓ dividing by x (x ≠ 0)
         𝑦 = 1 + 𝑥 − 𝑥 −1                            A✓ 1 + 𝑥 − 𝑥 −1
         𝑑𝑦
            = 1 + 𝑥 −2
         𝑑𝑥                                          CACA✓✓each derivative                    (4)
                                                                                              [12]

QUESTION 10
 10.1.1 𝑥 3 + 5𝑥 2 − 8𝑥 − 12 = 0
         (𝑥 + 1) is a factor 𝑓(−1) = 0
         (𝑥 + 1)(𝑥 2 − 4𝑥 − 12) = 0                          A ✓𝑓(−1) = 0                        (6)
                                                             A ✓(𝑥 + 1)(𝑥 2 − 4𝑥 − 12) = 0
         (𝑥 + 6)(𝑥 + 1)(𝑥 − 2) = 0
                                                             A✓ all three factors
         𝑥 = −6 𝑜𝑟 𝑥 = −1 𝑜𝑟 𝑥 = 2                           CACACA✓✓✓each value
                                                             Answer only 3/6 Marks
 10.1.2 𝑓(𝑥) = 𝑥 3 + 5𝑥 2 − 8𝑥 − 12
        𝑓 / (𝑥) = 3𝑥 2 + 10𝑥 − 8 = 0                         A✓derivative and equal to 0
        (3𝑥 − 2)(𝑥 + 4) = 0                                  CA✓factors
               2
        𝑥 = 𝑜𝑟 𝑥 = −4                                        CA✓x – values
               3
             2     2 3      2 2      2       400
        𝑓 ( ) = ( ) + 5 ( ) − 8 ( ) − 12 = −
             3     3        3        3       27
                        = −14,81                             CA✓y – value
             2                                                                                   (4)
        𝐵 ( ; − 14,81)
             3
 10.1.3 𝑓 ′′ (𝑥) = 6𝑥 + 10 = 0                               CA✓second derivative and
                                                             equal to 0
                     5                                       CA✓answer                           (2)
         𝑥=−
                     3
         OR                                                  OR
                 2
                     + (−4)        5                         CA✓subst. into midpoint
         𝑥=3                  =−                             formula                             (2)
                         2         3                         CA✓answer
         OR                                                  OR
                      𝑏    5                                 A✓formula                          (2)
         𝑥=−            =−
                     3𝑎    3                                 CA✓answer

### Page 12

Downloaded from hlayiso.com
Mathematics P1                            12                       September 2019 Preparatory Examination
                                           NSC Marking Guideline
 10.2.1 𝑓 / (0) = −8                                          CA✓gradient                         (2)
        𝑦 = −8𝑥 − 12                                          CA✓answer
 10.2.2 𝑓 ′ (𝑥). 𝑔′ (𝑥) > 0
         Since 𝑔′ (𝑥) < 0 for all 𝑥 ∈ 𝑅
                                                              A✓𝑔′ (𝑥) < 0
          (3𝑥 2 + 10𝑥 − 8) < 0
         (3𝑥 − 2)(𝑥 + 4) < 0                                  CA✓factors
                   2
         −4 < 𝑥 < 3                                           CA✓answer                           (3)
         OR                                                   OR
                      2                                       CACA ✓✓end points
         −4 < 𝑥 <
                      3                                       A✓interval                          (3)
                                                                                                 [14]

QUESTION 11

 11.1    𝛥𝑃𝑄𝐵:
         PQ
            = 𝑡𝑎𝑛 6 0∘
         2𝑦                                                 A✓ 𝑡𝑎𝑛 6 0∘
         ∴ PQ = 2√3𝑦                                        A✓setting up ratio
         QR = 𝑑 − 4𝑦                                        A✓value of PQ
                                                                                                    (4)
         A = 2√3𝑦(𝑑 − 4𝑦)                                   A✓value of QR

         OR                                                 OR
         ∆𝐴𝑃𝑆 is equilateral
         AP = PS = AS = 𝑑 − 4𝑦                              A✓value of PS
                                                            A✓value of SC
         SC = 4𝑦
         SR2 = (4𝑦)2 − (2𝑦)2 = 12𝑦 2                        A✓use of theorem of Pythagoras

         SR = 2√3𝑦                                          A✓value of SR
         A = 2√3𝑦(𝑑 − 4𝑦)                                                                           (4)
 11.2            A = 2 3 y (d − 4 y ).
                   = 2 3 yd − 8 3 y 2
                                                            A✓expression for Area
             A/ = 2 3d − 16 3 y = 0                         CA✓derivative and equal to 0
         d − 8y = 0
                  d
              y=                                            CA✓y – value
                  8

### Page 13

Downloaded from hlayiso.com
Mathematics P1                                 13                       September 2019 Preparatory Examination
                                                NSC Marking Guideline
                      d        d                             CA✓substitution into original
          Max A = 2 3.  d − 4                              equation
                      8        8 
                       3d    d                                 CA✓simplifying
                  =       d − 
                       4     2
                       3d  d     3d 2                          CA✓answer
                  =        =                                                                           (6)
                       4 2       8

                                                                                                        [10]

QUESTION 12

 12.1                 18 17                                        18        17
         P(GG) =         .                                    A✓        A✓
                      40 39                                        40        39
             51
         =       𝑜𝑟 0.1962 𝑜𝑟 19.62%                          A✓answer in any form                      (3)
             260
 12.2                     12   10 10   12                          12   10        10   12
         P(B and R) =        .   +   .                        A✓40 .         A✓40 .
                                                                        39             39
                          40   39 40   39
                               2                              A✓answer in any form
              P(B and R) =       𝑜𝑟 0,1538 𝑜𝑟 15,38 %                                                    (3)
                              13
                                                                                                         [6]

QUESTION 13
 13.1 9 x 9 x 9 = 729                                       A✓9 x 9 x 9                                  (2)
                                                            A✓729

 13.2    5 x 8 x 7 = 280                                    A✓5 x 8 x 7
                                                            A✓280
         OR                                                                                              (2)
                                                            OR
              5        8 digits     7 digits   56 ways
              6        8 digits     7 digits   56 ways
              7        8 digits     7 digits   56 ways
                                                            A✓table
              8        8 digits     7 digits   56 ways
              9        8 digits     7 digits   56 ways
                                     Total     280 ways     A✓answer                                     (2)

 13.3    9 x 1 x 9 = 81                                     A✓9 x 1 x 9                                  (2)
                                                            A✓81
                                                                                                         [6]
                                                                                                    Total : 150

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