to get the inverse relation of any expression, simply start off by doing a switcharoo on the variables, and then solve or "y".
[tex]\bf \boxed{y}=\boxed{x^2}+2\qquad inverse\implies \boxed{x}=\boxed{y^2}+2
\\\\\\
x-2=y^2\implies \sqrt{x-2}=y\impliedby f^{-1}(x)[/tex]
