Page 33 - E-MODUL FUNGSI KOMPOSISI DAN FUNGSI INVERS

KUNCI JAWABAN

Latihan soal pembelajaran 1
No Jawaban Skor
1. a. (g o f) (x) = g (f(x))

= g (3x + 2)

= 4 ( 3 + 2 )
10
= 4 (3x + 2) (3x + 2)
2
= 4 (9 + 12x +4)
2
= 36 + 48x + 14
b. ( f o g) (x) = f (g(x))

= f ( 4 )
2

2
= 3 ( 4 ) + 2

2
= 12 + 2
2
f o g (3) = 12(3) + 2 10
= 12 (9) + 2

= 108 + 2

= 110

2. g (f(x)) = f (g(x))

g (7x + 3) = f (3x + k)

3 (7x + 3) + k = 7 (3x + k) + 3

21x + 9 + k = 21x + 7k + 3

k – 7k = 3 – 9
20
−6k = −6

−6
k =
−6
k = 1

Jadi, nilai k adalah 1.

3. f o g (x) = f (g (x))

f (g (x)) = 4x – 2

19