Question

If f(x) = 5x + 4, which of the following is the inverse of Ax)?

O A. F'(x) = META
OB. F'(x) = 5x-4
O c. f() = 4 - 5x
O D. F"(x) = x-5

Answer 1

`f^(-1)` (x) =
`(x-4)/(5)`

Explanation:

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

y = 5x + 4 ( subtract 4 from both sides )

y - 4 = 5x ( divide both sides by 5 )

`(y-4)/(5)` = x

change x to
`f^(-1)`(x) and y back to x, thus

`f^(-1)`(x) =
`(x-4)/(5)`