Which equation is the inverse of y= 9x-4?

We need to determine the equation solving for x, because x is the inverse of y. The inverse of the function is written as y⁻¹

y = 9x - 4
switch the side, so x will be on the left side
9x - 4 = y

move 4 to the right side, substraction becomes addition
9x = y + 4

move 9 to the right side, multiplication becomes division
x = 

Switch x with invers of y, switch y with x. The invers is as written below.
y⁻¹ =

Y= x-3