Question 157492
I'll do the first one to get you going in the right direction


I'm assuming that the notation x->3x means {{{f(x)=3x}}}. 



{{{f(x)=3x}}} Start with the given function



{{{y=3x}}} Replace f(x) with y



{{{x=3y}}} Switch x and y



{{{x/3=y}}} Divide both sides by 3 to isolate y



So the answer is {{{y=x/3}}} which means that the inverse function is *[Tex \LARGE f^{-1}\left(x\right)=\frac{x}{3}]