Jika diketahui f(x)=2x-4 dan (gof) (x) = 4x^2-24x+32 maka g(x)

Diket : f(x) = 2x-4
           (gof)(x) = 4x²-24x+32

Ditanya : g(x) = ?

Jawab : 
* a = 2x-4
a+4 = 2x
a+4 / 2 = x

*(gof)(x) = 4x²-24x+32
   g(f(x)) = 4x²-24x+32
 g(2x-4) = 4x²-24x+32
      g(a) = 4(a+4/2)²-24(a+4/2)+32
      g(a) = 4(a²+8a+16/4)-12a+48+32
      g(a) = a²+8a+16-12a+80
      g(a) = a²-4a+96
      g(x) = x²-4x+96

(g o f) (x) =4x²-24x+32
g(f(x))=4x²-24x+32
g(2x-4)=4x²-24x+32
Missal. 2x-4=a
2x=a-4
g(a)=2(2(a+4)²-12(2(a+4))+32
=2(2a+4)²-12(2a+8)+32
=2(4a²+32a+64)-24a+96+32
=8a²+64a+128-24a+96+32
g(a) =8a²+40a+256
g(x)=8x²+40x+256