Question

Find an expression for f−1(x), if f(x) = 5 − 2x

Answer 1

`f^(-1)`(x) =
`(5-x)/(2)`

Explanation:

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

y = 5 - 2x ( add 2x to both sides )

2x + y = 5 ( subtract y from both sides )

2x = 5 - y ( divide both sides by 2 )

x =
`(5-y)/(2)`

Change y back into terms of x

`f^(-1)` (x) =
`(5-x)/(2)`