If [tex]$f(x) = 5x$[/tex], what is [tex]$f^{-1}(x)$[/tex]?

A. [tex]$f^{-1}(x) = -5x$[/tex]
B. [tex]$f^{-1}(x) = -\frac{1}{5}x$[/tex]
C. [tex][tex]$f^{-1}(x) = \frac{1}{5}x$[/tex][/tex]
D. [tex]$f^{-1}(x) = 5x$[/tex]



Answer :

Sure, let's derive the inverse of the function [tex]\( f(x) = 5x \)[/tex] step by step.

### Step-by-Step Solution:

1. Start with the given function:
[tex]\[ f(x) = 5x \][/tex]

2. Replace [tex]\( f(x) \)[/tex] with [tex]\( y \)[/tex] for easier manipulation:
[tex]\[ y = 5x \][/tex]

3. To find the inverse function [tex]\( f^{-1}(x) \)[/tex], solve this equation for [tex]\( x \)[/tex] in terms of [tex]\( y \)[/tex]:
[tex]\[ y = 5x \][/tex]

4. Isolate [tex]\( x \)[/tex] by dividing both sides of the equation by 5:
[tex]\[ x = \frac{y}{5} \][/tex]

5. Now, express [tex]\( x \)[/tex] in terms of [tex]\( y \)[/tex], which can now be replaced back with [tex]\( x \)[/tex] since we're defining the inverse function:
[tex]\[ f^{-1}(x) = \frac{x}{5} \][/tex]

6. Simplify the expression:
[tex]\[ f^{-1}(x) = \frac{1}{5}x \][/tex]

Hence, the inverse function [tex]\( f^{-1}(x) \)[/tex] is:

[tex]\[ f^{-1}(x) = \frac{1}{5}x \][/tex]

The correct answer is:
[tex]\[ f^{-1}(x) = \frac{1}{5} x \][/tex]