Question

Express your answer as a polynomial in standard form.

f(x) = x + 7
g(x) = x2 + 2x
1
Find: g(f(x))

Answer 1

x² + 16x + 64

Explanation:

To find f(g(x)) , substitute x = g(x) into f(x), that is

f(x + 7)

= (x + 7)² + 2(x + 7) + 1 ← expand (x + 7)² using FOIL

= x² + 14x + 49 + 2x + 14 + 1 ← collect like terms

= x² + 16x + 64