as you already know, to get the inverse of any expression we start off by doing a quick switcheroo on the variables and then solve for "y".
[tex]\bf \stackrel{f(x)}{y}=x^2-10\implies \stackrel{switcheroo}{x=y^2-10}\implies x+10=y^2\implies \sqrt{x+10}=\stackrel{f^{-1}(x)}{y}[/tex]
