Jika diketahui nilai (f°g°h) (x) = 2x²+2x+4 dan nilai (g°h) (x) =4x-2, maka f(x) adalah...

(f•g•h)(x) = f (g•h)(x)
2x^2 +2x+4 = f(4x-2)

Misal : y = 4x-2
4x-2 = y
4x = y + 2
x = y/4 + 1/2

(f•g•h)(x) = f (g•h)(x)
2x^2 +2x+4 = f(4x-2)
2{(y+2)/4}^2 +2{(y+2)/4} +4 = f(y)

f(y) = 2{(y+2)/4}^2 +2{(y+2)/4} +4

f(y) = (y^2 +4y+4)/8 + (y+2)/2 + 4

f(y) = (y^2)/8 + y + 11/2
f(x) = (x^2)/8 + x + 11/2