Question

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

Answer 1

Answer:

$f^{-1}$ (x) = $\frac{x-4}{5}$

Step-by-step 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 )

$\frac{y-4}{5}$ = x

change x to $f^{-1}$(x) and y back to x, thus

$f^{-1}$(x) = $\frac{x-4}{5}$