Question 257232
We start with 
{{{f(x) = 3x – 7}}}
step 1 - reverse x and y to get
(ii) {{{x = 3y - 7}}}
add 7 to get
(iii) {{{x+7 = 3y}}}
divide by 3
(Iv) {{{y^-1 = (1/3)x + (7/3)}}}