Chapter 6 Rational Exponents and Radical Functions - 6.4 Use Inverse Functions - Guided Practice for Examples 1, 2, and 3 - Page 439: 3

$$y=-\frac{x-1}{3}$$

Switching the elements of the domain and the range (in other words, the dependent and independent variables), we find that the inverse is: $$x=-3y+1 \\ y=-\frac{x-1}{3}$$ Note, if we plug the inverse into the original function or the original function into the inverse, we should get x.