f(x)=4x+20 Inverse function

Answer 1

given function is f(x) = 4x + 20

let y = 4x + 20

rearrange (to make x subject) to get y - 20 = 4x => x = (y - 20) / 4

swap x and y naming so y = (x - 20) / 4

and inverse notation f^-1(x) = ^{(x - 20)} / ₄

Answer 2

To find the inverse function you do the following: y=4x+20 or 4x=y-20 or x=(1/4)y-5. Therefore, the inverse function is given by the formula f^{-1}(x)=(1/4)x-5.