If f(x) = (1)/(9) x-2, what is F^(-1)(x)

Question

If f(x) =
`(1)/(9)` x-2, what is
`F^(-1)`(x)

Answer 1

Solution given:

f(x) =
`(1)/(9)` x-2

let f(x)=y

y =
`(1)/(9)` x-2

interchanging role of x and y

x=
`(1)/(9)` y-2

x+2=
`(1)/(9)` y

y=9(x+2)

y=9x+18

So

F-¹(x)=9x+18

and

F-¹(-1)=9*-1+18=-9+18=9