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                                                                               Mathematics  Form 3  Chapter 9 Straight Lines     Mathematics  Form 3  Chapter 9 Straight Lines

                              PT3 Standard Practice  9                 Section B                                                 (b)  Equation of line PQ                       2.  (a)  (i)   k located at line y = 3
                                                                                                                                      y = –  5  x + 5 ..............(1)                    Therefore k(a, 3)
                     Section A                                           1.          Diagram             Equation                          3                                               y = 2x – 4
                                                                                       Rajah             Persamaan                   Equation of line RS
                                          6 – (–4)                                                                                                                                           3 = 2(a) – 4
                       1.  Gradient of KL =                                 (a)        y                                              y = x + 3 ....................(2)
                                          8 – (–2)                                                                                                                                         a = 3.5
                                        = 1                                        K  2                 y = –    + 2                 (1) = (2),                                            ∴ k(3.5, 3)
                                                                                                              2
                                                                                                                                                     
                          Equation of KL                                                            x         5                       –   5  x + 5 = x + 3  × 3
                          y = x + c                                                   O       5  L                                      3                                              (ii)  x = –4
                          at L(8, 6)                                         (b)                                                     –5x + 15 = 3x + 9                                (iii)  m ML  = m KN
                          6 = 8 + c                                                    y                                                    x =   3                                            = 2
                          c  = –2                                                                K(8, 4)                                       4
                                                                                                               1                                   3                                       y = 2x + c
                          ∴ y = x – 2                                                                      y =  x                    Substitute x =    into (2)
                                                                                                   x           2                                   4                                       Substitute x = –4, y = 0,
                          Answer: D                                               L   O                                              y =   3   + 3
                                                                                                                                         4                                                 0 = 2(–4) + c
                       2.   4x + 3y = 15                                                                                             y =   15                                              c  = 8
                              3y = –4x + 15                              2.       Equation           Point                               4                                                 ∴ y = 2x + 8
                                     4                                            Persamaan           Titik                               3 15
                                y = –   x + 5                                                                                         ∴ k   ,                                        (iv)  Coordinates P = (p, 0)
                                     3                                                                                                    4  4
                                                                            (a)  y = 3x – 7         (6, 11)     ✓                                                                          Substitute x = p, y = 0 into y = 2x – 4,
                                  4
                          ∴ m = –  , c = 5                                                                                       (c)  Substitute x = 2, y = 8,                             0 = 2p – 4
                                  3
                                                                            (b)  –5x + y = 2       (–3, –13)    ✓                      y =   k  x + 5m                                     p = 2
                          Answer: B                                                                                                       3                                                Length of MP  = 2 – (–4)
                                                                                     1
                       3.  x-intercept, y = 0                               (c)  3y =  x + 8        (2, –3)     ✗                     8 =  2k  + 5m                                                     = 6 units
                                                                                     2                                                     3
                            2x – 3y = 6                                                                                               24 = 2k + 15m ...................(1)                 Area of KLMP = (3 × 6)
                                                                                      1
                           2x – 3(0) = 6                                    (d)   1 y +  x = 1      (–10, 6)    ✗                    Substitute x = –5, y = –13                                         = 18 units 2
                                2x = 6                                          3     5                                                    k
                                 x = 3                                                                                                 y =   x + 5m                               (b)  2x + 3y – 4 = 0
                                                                       Section C                                                           3                                                   3y = –2x + 4
                          ∴ x-intercept = 3                                                                                          –13 =   –5k   + 5m
                                                                                                                                                                                                      2
                                                                         1.  (a)  (i)   Rhombus has equal length of sides.                  3                                                   y = –   x +   4
                          Answer: B                                                                                                                                                                   3    3
                                                                                    OK = KL = LM = MO                                 –39 = –5k + 15m ...............(2)                              2
                                                                                               2
                       4.  m KL  = –1, c = –5                                       OK = (–5)  + 12 2                              (1) – (2)                                         gradient, m = –   3
                                                                                       = 13 units                                    24 – (–39) = 2k – (–5k)
                          ∴ equation of the straight line KL is                                                                                                                   (c)  5x + 2y = 8
                              y = –x – 5                                            ∴ OM = 13 units                                         63 = 7k
                                                                                        M(–13, 0)                                            k = 9                                     Divide both sides by 8,
                          Answer: C                                                                                                  Substitute k = 9 into (1)                         5x   2y    8
                                                                               (ii)  m KO  =   12 – 0                                                                                  8   +    8   =   8
                                   2                                                      –5 – (0)                                    24 = 2(9) + 15m
                       5.      y –  x = 5                                                                                                                                               x   y
                                   3                                                    = –  12                                      15m = 6                                           8   +    = 1
                                                                                                                                                                                            4
                              3y – 2x = 15                                                   5                                             2
                           2x – 3y + 15 = 0                                          y = mx + c                                        m =  5                                          5
                                                                                          12                                                                                           Therefore, x-intercept =   8
                          Answer: C                                                  y = –   x + c                                   ∴ m =   2  , k = 9                                                       5
                                                                                           5                                                5                                          y-intercept = 4
                                                                                    Substitute x = 0, y = 0,
                                                                                    c = 0
                                                                                    Equation of LM

                                                                                    y = –  12 x
                                                                                          5
                                                                                (iii)  y = 12
                                                                    53                         © Penerbitan Pelangi Sdn. Bhd.  © Penerbitan Pelangi Sdn. Bhd.             54

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                BOOKLET ANS MATH F3.indd   28                                                                                                                                                                    03/01/2020   10:21 AM
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