Question

F (x) = x^2 + 2x - 5
g(x) = 2x + 4
What is (f• g)(x)?

Answer 1

Explanation:

This is a composite function, f(g(x)). This means, working from the inside function to the outside, we will take the function g and plug it in for x in the f function. g(x) = 2x + 4. We will plug that into f(x) and evaluate f(2x+4):

`f(g(x))=(2x+4)^2+2(2x+4)-5` and I imagine your teacher has you simplify completely. We FOIL and distribute to get

`f(g(x))=4x^2+16x+16+4x+8-5` which, by combining like terms, give us

`f(g(x))=4x^2+20x+19`