Given two functions:

f(x)=sqrt(4-x)

g(x)=x^2

Find the range of gof:

gof(x)=4-x

Shouldn't the range be all real numbers? Because it is a linear function. But the answer key says [0,infinity[ ??

Next question:

Given two functions:

f(x)=1/x (x cannot be 0)

g(x)1/x^2 (x cannot be 0)

Find the range of fog

fog(x)=x^2

Shouldn't the range by [0,infinity[ ?? The answer key says ]0,infinity[

Can someone please help me out -3-, I am so frustrated...