Question

Help help help help thanks lol

Answer 1

$f(x)=x^2-81\\ y=x^2-81\\ x^2=y+81\\ x=\pm \sqrt{y+81}\\ f^{-1}(x)=\pm \sqrt{x+81}$

$f(x)=2x-6\\ y=2x-6\\ 2x=y+6\\ x=\dfrac{1}{2}y+3\\ f^{-1}(x)=\dfrac{1}{2}x+3\\ f^{-1}(2)=\dfrac{1}{2}\cdot2+3\\ f^{-1}(2)=1+3\\ f^{-1}(2)=4$