Question

Let f(x) = 5x + 4 and g(x) = x2 - 4. Find the following.
(gof)(-2)

Answer 1

(g ￮ f)(-2) = 32

Explanation:

Given

`f(x)=5x+4`

`g\left(x\right)=x^2-4`

We have to evaluate (g ￮ f)(-2), so first we will evaluate f(-2) then use this value to evaluate g(x).

Finding f(-2)

`f(x)=5x+4`

`f(-2) = 5(-2)+4`

`= -10 + 4`

`= -6`

Then

`g\left(-6\right)=\left(-6\right)^2-4`

`=36-4`

`= 32`

Therefore,

(g ￮ f)(-2) = 32