Question

Which function is the inverse of f(x) = -5x-4?

Answer 1

B

Explanation:

Since g(f(x))=x g ( f ( x ) ) = x , f−1(x)=x5+45 f - 1 ( x ) = x 5 + 4 5 is the inverse of f(x)=5x−4 f ( x ) = 5 x - 4 .

Answer 2

B.
`-(1)/(5) x+(4)/(5)`

Explanation:

1. Rewrite the function as a linear equation:

y = -5x - 4

2. Swap x and y:

x = -5y - 4

3. Solve for y:

x+4 = -5y - 4+4

x + 4/-5 = -5y/-5

`(x+4)/(-5)` = y can be rewritten as
`-(1)/(5) x+(4)/(5)`

4. Write in inverse notation:

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

Therefore, B is the answer.