Question

What is f(g(x)) when f(x) = 5x + 3, and g(x) = 3x2 + 3?

A) f(g(x)) = 8x^2 + 6
B) f(g(x)) = 15x^2 + 18
C) f(g(x)) = 75x^2 + 90x + 30
D) f(g(x)) = 255x^2 + 270x + 84

Answer 1

B) f(g(x)) = 15x² + 18

Explanation:

Plug the entire equation of g(x) in for the x in f(x)

f(g(x)) = 5(3x² + 3) + 3

f(g(x)) = 15x² + 15 + 3

f(g(x)) = 15x² + 18