Misal f (x) = 3x2 -1 dan g (x) = 2X -1 / X+2 nilai dari (fog)(3)

g(x) = (2x - 1)/(x + 2)
g(3) = (2.3 - 1)/(3 + 2)
g(3) = 5/5
g(3) = 1

f(x) = 3x² - 1

(fog)(3)
= f(g(3))
= f(1)
= 3.1² - 1
= 3 - 1
= 2