Question

Find the inverse of the function: f(x)=1/5x+4

A f−1(x)=x−4

B f−1(x)=5x−20

C f−1(x)=−5x−4

D f−1(x)=4x−5

Answer 1

B.
`{f}^( - 1) (x) = 5x - 20`

Explanation:

`f(x) = (1)/(5) x + 4`

`y = (1)/(5) x + 4`

`x = (1)/(5) y + 4`

`(1)/(5) y + 4 = x`

`y + 20 = 5x`

`y = 5x - 20`

`\boxed{\green{{f}^( - 1) (x) = 5x - 20}}`