Chapter 6 Rational Exponents and Radical Functions - 6.4 Use Inverse Functions - 6.4 Exercises - Skill Practice - Page 443: 43

$$y=\sqrt[4]{x+9},\:y=-\sqrt[4]{x+9}$$

Switching the elements of the domain and the range (in other words, the dependent and independent variables), we find that the inverse is: $$x=y^4-9 \\ y=\sqrt[4]{x+9},\:y=-\sqrt[4]{x+9}$$