Question

Given `f(x) = 2x - 5` and `g(x) = 2x^2 + 7` how do you find f(g(x))?

Answer 1

`f(g(x)) = 4x^2 + 9`

Explanation:

`f(x) = 2x - 5`

`g(x) = 2x^2 + 7`

To find `f(g(x))`, what you need to do is plug `g(x)` for each occurence of `x` in `f(x)`:

`f(color(blue)(x)) = 2color(blue)(x) - 5`

`f(g(x)) = f(color(blue)(2x^2+7)) = 2 (color(blue)(2x^2+7)) - 5`

`= 4x^2 + 14 - 5 = 4x^2 + 9`