If [tex]\( f(x) = \frac{1}{9}x - 2 \)[/tex], what is [tex]\( f^{-1}(x) \)[/tex]?

A. [tex]\( f^{-1}(x) = 9x + 18 \)[/tex]

B. [tex]\( f^{-1}(x) = \frac{1}{9}x + 2 \)[/tex]

C. [tex]\( f^{-1}(x) = 9x + 2 \)[/tex]

D. [tex]\( f^{-1}(x) = -2x + \frac{1}{9} \)[/tex]



Answer :

To find the inverse of the function [tex]\( f(x) = \frac{1}{9}x - 2 \)[/tex], let's perform the following steps:

1. Start with the function:
[tex]\[ y = \frac{1}{9}x - 2 \][/tex]

2. Swap [tex]\( x \)[/tex] and [tex]\( y \)[/tex]:
[tex]\[ x = \frac{1}{9}y - 2 \][/tex]

3. Solve for [tex]\( y \)[/tex]:

First, isolate the term with [tex]\( y \)[/tex] on one side of the equation:
[tex]\[ x + 2 = \frac{1}{9}y \][/tex]

Next, multiply both sides of the equation by 9 to solve for [tex]\( y \)[/tex]:
[tex]\[ 9(x + 2) = y \][/tex]

Therefore,
[tex]\[ y = 9x + 18 \][/tex]

4. Write the inverse function:
[tex]\[ f^{-1}(x) = 9x + 18 \][/tex]

So, the inverse function is [tex]\( f^{-1}(x) = 9x + 18 \)[/tex]. Thus, the correct answer is:
[tex]\[ f^{-1}(x) = 9x + 18 \][/tex]

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