Question

F(x)=2x+1 and g(x)=x^2-7, find (f g) (x)

Answer 1

The answer is (f o g)(x) = 2x^2 - 13

In order to find a composite function, you take the first letter (in this case f) and use that equation. You then remove the variable and put in the second letter (g).

f(x) = 2x + 1 ----> Remove variable.

f(x) = 2(      ) + 1 ----> Insert g(x)

(f o g)(x) = 2(x^2 - 7) + 1 ----> Distribute

(f o g)(x) = 2x^2 - 14 + 1 ----> Simplify

(f o g)(x) = 2x^2 - 13