Question

The inverse of f(x)=7x+9 ?

Answer 1

`f^(-1)` (x) =
`(x-9)/(7)`

Explanation:

let y = f(x) and rearrange making x the subject

y = 7x + 9 ( subtract 9 from both sides )

y - 9 = 7x ( divide both sides by 7 )

`(y-9)/(7)` = x

change y back into terms of x with x =
`f^(-1)` (x) , then

`f^(-1)` (x) =
`(x-9)/(7)`