Question

4. f(x) = x² – 5 (if x 20) and g(x) = (x + 5

Answer 1

Evaluating functions means to substitute the values at every occurrence of x.

So, we have

$f(x)=x^2-5 \implies f(20)=20^2-5 = 400-5=395$

You didn't specify where we should evaluate g(x).