recall that 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}=2x\implies \stackrel{\textit{switcheroo}}{x=2y}\implies \cfrac{x}{2}=y\implies \cfrac{1}{2}x=\stackrel{f^{-1}(x)}{y}[/tex]
