jika f(x) = 3x, g(x) = x + 1. tentukan (fog)(x) dan (fog)^-1(x)

jawab

f(x)= 3x
g(x) = x+ 1

fog(x) = f{g(x)} = f(x+1)
fog(x) = 3(x+1) = 3x  + 3

(fog)⁻¹(x) =
(fog)(x)= = 3x + 3
(fog)⁻¹ (3x+3) = x
y = 3x + 3
3x  = y - 3
x = 1/3 y  - 1

(fog)⁻¹(y) = 1/3 y - 1
(fog)⁻¹(x) = 1/3 x  - 1