Question

Jika f(x) = 2x+3 dan (f o g) =2x²+6x-7, maka g(x)adalah...
A. 2x²+6x-10
B. 2x²+6x-7
C. 2x²+6x-4
D. x²+3x-2
E. x²+3x-5

Answer 1

F(x) = 2x+3
(fog) = 2x²+6x-7
(fog) = f(g(x))
2x²+6x-7 = 2g(x) + 3
2g(x) = 2x²+6x-10
g(x) = (2x²+6x-10)/2
g(x) = x²+3x-5 (E)

Answer 2

(fog)(x) = 2x² + 6x - 7    dan   f(x) = 2x + 3
f(g(x)) = 2x² + 6x - 7 
2(g(x)) + 3 = 2x² + 6x - 7
2g(x) = 2x² + 6x - 10
g(x) = x² + 3x - 5
                 Jawaban (E)