Page 7 - Top Class Additional Mathematics Tg 4

Additional Mathematics Form 4 Chapter 1 Functions

(a) Given f : x → 4x – a, where a is a constant and f(–1) = –11. Find
Diberi f : x → 4x – a, dengan keadaan a ialah pemalar dan f(–1) = –11. Cari
(i) the value of a.
nilai a.
(ii) the value of x when f(x) = –19.
nilai x apabila f(x) = –19.

(i) f(x) = 4x – a (ii) f(x) = 4x – 7
f(–1) = 4(–1) – a 4x – 7 = –19
–4 – a = –11 4x = –12
a = 7 x = –3

(b) A function is defined by h : x → 6x – 5. Find
Suatu fungsi ditakrifkan oleh h : x → 6x – 5. Cari
(i) the image of object 2.
imej bagi objek 2.
(ii) the object which maps onto itself.
objek yang memeta kepada dirinya sendiri.

(i) h(x) = 6x – 5 (ii) f(x) = 6x – 5
h(2) = 6(2) – 5 6x – 5 = x
= 7 5x = 5
x = 1

2
(c) Given g : x → px – qx, where p and q are constants. If g(3) = 12 and g(4) = 28, find the values of p and q.
Diberi g : x → px – qx dengan keadaan p dan q ialah pemalar. Jika g(3) = 12 dan g(4) = 28, cari nilai p dan q.
2
2
g(x) = px – qx Substitute  into :
2
g(3) = p(3) – q(3) 4p – (3p – 4) = 7
9p – 3q = 12 4p – 3p + 4 = 7
3p – q = 4 –––  p = 3

g(4) = p(4) – q(4) Substitute p = 3 into :
2
16p – 4q = 28 q = 3(3) – 4
4p – q = 7 –––  = 5

From : q = 3p – 4 ––– 

(d) Given the function h : x → 4 – x. Find the value of x when h(x) = 7.
Diberi fungsi h : x → 4 – x. Cari nilai x apabila h(x) = 7.

h(x) = 4 – x and
4 – x = 7 4 – x = –7
4 – x = 7 x = 11
x = –3

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