To find the inverse of a function switch the place of y (aka f(x) ) with x. Then solve for y.
Original equation:
y = 2x + 17
Switched:
x = 2y + 17
Solve for y by isolating it:
x - 17 = 2y + 17 - 17
x - 17 = 2y
(x - 17)/2 = 2y/2

Hope this helped!
~Just a girl in love with Shawn Mendes