Diketahui f(x) = √3x - x√5 dan g(x) = x + 5. Nilai (f o g) (5) sama dengan..

(fog) (x) = f(g(x))
= f(x+5)
= √3(x+5)-(x+5)√5
= √3x+15 - x+5√5

Jika fog (5) maka :
(fog) (5) = √3(5)+5 - (5)+5√5
= √15+15 - 10√5
= √30 - 10√5

Jadi, (fog) (5) = √30 - 10√5