Question

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

O A. f-1(x) = x-5
4
O B. f-¹(x) = X54
x-4
O C. f¹(x) = 5x-4
OD. f(x)=4-5x

Answer 1

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

Explanation:

1. replace f(x) with x, and x with y: x=5y+4

2. solve for y: x=5y+4

⇒ x-4=5y

⇒ (x-4)/5=y

3. replace y with f⁻¹(x)