Question

Find f-1(x) if f(x) = 4x + 5.​

Answer 1

Answer:

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

Step-by-step explanation:

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

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

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

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

Change y back into terms of x

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

Answer 2

Answer:

(x - 5)/4

Step-by-step explanation:

y = 4x + 5

Make x the subject

x = (y - 5)/4

Interswitch x and y

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