Question

F(×)=4x^2-×

G(x)=4x+4
Find f(-5) and g(-7)

Answer 1

c'mon -- surely by now you know that x is just a place holder, and can be replaced by any value you choose. Your notation is a bit unclear, but let's go with

f(x) = 4x^(2-x) so
f(-5) = 4(-5)^(2-(-5)) = 4(-5)^7 = -4*5^7
similarly, g(-7) = 4(-7)+4 = -26