Algebra

y=3x+12    Solve for 'x'

(y-12)/3 = x       then switch the 'x' and 'y's

(x-12)/3 = y

 

or    y = 1/3 x -4

Flip the x and the y, so it becomes \(x=3y+12\)

Then just solve for y

\(x-12=3y+12-12\)

\(\frac{x-12}{3}=\frac{3y}{3}\)

\(\frac{x}3-4=y\)

So the inverse is \(\frac{x}3-4=y\)