tolong Jawab Beserta caranya...trima kasih

f(g(x)) = x^2 - x - 7
f(x - 2) = x^2 - x - 7

misal p = x-2
x = p+2
maka:
f(x) = (p+2)^2 -(p+2) - 7
f(x) = p^2 + 4p + 4 - p - 2 - 7
f(x) = p^2 + 3p -5
f(x) = x^2 + 3x - 5