jika f(x+2)=x²+2x+1 dan g(x-2) =x²-2x+1 maka (fog) (1)

f(x + 2) = x² + 2x + 1
g(x - 2) = x² - 2x + 1

maka
g(1)
= g(3 - 2)
= 3² - 2(3) + 1
= 9 - 6 + 1
= 4

f(4)
= f(2 + 2)
= 2² + 2(2) + 1
= 4 + 4 + 1
= 9

jadi (fog)(1)
= f(g(1)))
= f(4)
= 9