Question

Find the inverse of y=(×-9)^2

Answer 1

To find the inverse of y=(×-9)^2 replace y with x and x with y and then solve for y.

$y=(x-9)^2$
$x=(y-9)^2$
$\pm \sqrt{x} = \sqrt{(y-9)^2}$
$\pm\sqrt{x} = (y-9)$
$\pm\sqrt{x} =y-9$
$\pm\sqrt{x} =y- 9 + 9$
$9 \pm\sqrt{x} = y$
$y = 9\pm\sqrt{x}$
$f(x)^{-1} = 9 \pm\sqrt{x}$