Jika (fog)(x) = 4x2+8x-3 dab g(x)=2x+4, maka f-1(x)=... a. x+9 b. 2+√x c. 2+√x+1 d. 2+√x+7 e. X2-2x-3

cari dulu f(x)

f(g(x)) = 4x^2 + 8x - 3
f(2x+4) = 4x^2 + 8x - 3
f(2x+4) = 4x^2 + 16x + 16 - 8x - 16 - 3
f(2x+4) = (2x + 4)^2 - 4(2x + 4) - 3
f(x) = x^2 - 4x - 3


f(x) = y
x^2 - 4x - 3 = y
x^2 - 4x - 3 + 7 = y + 7
x^2 - 4x + 4 = y + 7
(x - 2)^2 = y + 7
x - 2 = akar(y+7)
x = 2 + akar(y+7)

f-1(x) = 2 + akar(x + 7)