Question

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

Answer 1

Answer:

D.  $f^{-1}(x)=\frac{x-5}{2}$

Step-by-step 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

$\frac{x-5}{2} =y$

Hence $f^{-1}(x)=\frac{x-5}{2}$

Answer 2

Answer: OPTION D

Step-by-step 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:

$y-5=2x\\\\x=\frac{y-5}{2}$

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

$f^{-1}(x)=\frac{x-5}{2}$