bantuin ya, ada di foto. terimakasih :)

f(g(x)) = x^2 - 3x + 2
g(x) = x-2
maka
f(x-2) = x^2 - 3x + 2
misal x-2 = a ; x = 2+a
f(a) = (2+a)^2 - 3(2+a) + 2
f(a) = a^2-a
jadi f(x) = x^2-x
:)

(fog)(x) = x^2 - 3x + 2
g(x) = x-2

(fog)(x) = x^2 - 3x + 2
f(g(x)) = x^2 - 3x + 2
f(x-2) = x^2 - 3x +2

dimisalkan x-2 = y
x = y+ 2

f(x-2) = x2 - 3x + 2
f(y) = (y+2)^2 - 3(y+2) + 2
f(y) = y^2 + 4y + 4 - 3y - 6 + 2
f(y) = y^2 +y
f(x) = x^2 + x

semoga membantu :)