Question

PLEASE SOMEONE HELP I TRULY DO NOT UNDERSTAND

Answer 1

Hi there!

$\large\boxed{f^{-1}(x) = \sqrt[3]{\frac{x+4}{9} } }$

$f(x) = 9x^{3} - 4$

Find the inverse by replacing f(x) with y and swapping the x and y variables:

$x = 9y^{3} - 4$

Isolate y by adding 4 to both sides:

$x + 4 = 9y^{3}$

Divide both sides by 9:

$\frac{x+4}{9}= y^{3}$

Take the cube root of both sides:

$y = \sqrt[3]{\frac{x+4}{9} }\\\\f^{-1}(x) = \sqrt[3]{\frac{x+4}{9} }$