Question

F(x) = x + 7
Work out an expression for f-1(x).

Answer 1

If
`f^(-1)(x)` is the inverse of
`f(x)`, then

`f\left(f^(-1)(x)\right) = x`

Given
`f(x)=x+7`, the inverse is such that

`f\left(f^(-1)(x)\right) = f^(-1)(x)+7 = x`

Solve for
`f^(-1)(x)` :

`f^(-1)(x)+7=x \implies \boxed{f^(-1)(x)=x-7}`