Answer:
[tex]f^{-1}[/tex](x) =
Step-by-step explanation:
let y = f(x), then rearrange making x the subject
y = [tex]\frac{1}{5}[/tex]x + 4 ( subtract 4 from both sides )
y - 4 = [tex]\frac{1}{5}[/tex]x ( multiply both sides by 5 to clear the fraction )
5y - 20 = x
Change y back into terms of x with x = [tex]f^{-1}[/tex] (x) , then
[tex]f^{-1}[/tex] (x) = 5x - 20
