Given the function y, we want to find the inverse function y^-1.
Then, replace every x with a y and every y with an x. It yields,
[tex]x=3y+12[/tex]now, solve the equation for y. So, by subtracting 12 to both sides, we have
[tex]x-12=3y[/tex]or equivalently,
[tex]3y=x-12[/tex]and, by dividing both sides by 3, we obtain
[tex]y=\frac{x-12}{3}[/tex]Finally, replace y with y^-1. Then, the inverse function is given by:
[tex]y^{-1}=\frac{x-12}{3}[/tex]