Question

If f(x)= 2x + 5, which of these is the inverse of f(x)

Answer 1

Answer: OPTION D

Explanation:

To find the inverse of the function given in the problem, you must apply the proccedure shown below:

1- Rewrite the function:

`y=2x+5`

2- You must solve for x from the functionn, as following:

• Subtract 5 from both sides of the function.

• Divide both sides of the function by 2.

• Then:

`y-5=2x\\\\x=(y-5)/(2)`

• Rewrite the function as following (Substitute
  `x=f^(-1)(x)` and
  `y=x`:

`f^(-1)(x)=(x-5)/(2)`

Answer 2

D.
`f^(-1)(x)=(x-5)/(2)`

Explanation:

The given function is

`f(x)=2x+5`

Let
`y=2x+5`

Interchange x and y.

`x=2y+5`

Solve for y.

`x-5=2y`

Divide both sides by 2

`(x-5)/(2) =y`

Hence
`f^(-1)(x)=(x-5)/(2)`