Question

F(x) = 5x – 3 and g(x) = 5x – 4, find (fog)(x).

Answer 1

(fog)(x) = 25x - 23

Explanation:

• f(x) = 5x - 3
• g(x) = 5x - 4

(fog)(x) = f(g(x))

This is an example of a composite function.

Simply substitute g(x) for x into the function f(x) and simplify.

f(g(x)) = f(5x - 4)

• f(5x - 4) = 5(5x - 4) - 3

Distribute 5 inside the parentheses.

• f(g(x)) = 25x - 20 - 3

Combine like terms.

• f(g(x)) = 25x - 23

(fog)(x) = 25x - 23