Find the inverse of f(x) = 7x+4

To start make the equation equal y.
So y = 7x+4
Then rearrange the equation to make x the subject.
Subtract 4 from both sides: y-4 = 7x
Divide by 7: (y-4)/7 = x
Now write it in terms of x
f(x)^-1 = (x-4)/7
where f(x)^-1 means the inverse of f(x).