Answer
The statement does not make sense because $f(g(x))$ gives a completely different value than the problem assumes.
Work Step by Step
As demonstrated below, $f(g(x))$ does not yield $x^2+4$ like the problem states.
$f(x)=x^2$
$g(x)=x+4$
$f(g(x))=f(x+4)=(x+4)^2=x^2+8x+16$
$g(f(x))=g(x^2)=x^2+4$
