Question

Given the function f(x) = 2x, find the value of f−1(16).

Answer 1

8. 

First you must find the inverse of the function since that's what the f-1 means. You do this by switching the f(x) and the x and then solve for f(x). 

f(x) = 2x - switch them
x = 2f(x) - now divide the 2 away
x/2 = f(x) - now put the 16 in for x to find f-1(16)
16/2 = f(x) 
8 = f(x) 

Answer 2

Hi there! The answer is 8.

$f(x) = 2x$
First we need to find the inverse function.

$y = 2x$
Switch places of the variables.

$x = 2y$
Divide both sides of the equation by 2.

$\frac{1}{2} x = y$
Switch sides.

$y = \frac{1}{2} x$
Now we've found our inverse function.

$f {}^{ - 1} (x) = \frac{1}{2} x$
Plug in x = 16 into the formula.

$f {}^{ - 1} (16) = \frac{1}{2} \times 16 = 8$
Therefore, the answer is 8.
~ Hope this helps you!