Question 1090148
{{{f(3(3))=f(3)+2=5+2=7}}}
{{{f(9)=7}}}
So then,
{{{f(3(9))=f(9)+2=7+2=9}}}
{{{f(27)=9}}}
and,
{{{f(3(27))=f(27)+2=9+2=11}}}
{{{f(81)=11}}}
So,
{{{f^(-1)(11)=81}}}