I have the following equation:
$h(x) = (5-2x)^2$
Which can be rewritten as g of f of x if:
$g(x) = x^2 ; f(x) = 5 - 2x$
Now if I draw out the variations of the two functions and combine them, I get the opposite of what I should, I am aware that the source of the problem is that $f(x)$ could equally be $2x - 5$, but is there a mathematical reason for which this doesn't work?