Select the correct answer.

What is the inverse of the function [tex] f(x) = \frac{3 - x}{7} [/tex]?

A. [tex] f^{-1}(x) = 7x - 3 [/tex]
B. [tex] f^{-1}(x) = 3 - \frac{x}{7} [/tex]
C. [tex] f^{-1}(x) = \frac{7 + x}{3} [/tex]
D. [tex] f^{-1}(x) = 3 - 7x [/tex]



Answer :

To find the inverse of the function [tex]\( f(x) = \frac{3 - x}{7} \)[/tex], follow these steps:

1. Start with the given function:

[tex]\[ f(x) = \frac{3 - x}{7} \][/tex]

2. Replace [tex]\( f(x) \)[/tex] with [tex]\( y \)[/tex] for simplicity:

[tex]\[ y = \frac{3 - x}{7} \][/tex]

3. Interchange [tex]\( x \)[/tex] and [tex]\( y \)[/tex] to set up for solving the inverse:

[tex]\[ x = \frac{3 - y}{7} \][/tex]

4. Solve for [tex]\( y \)[/tex] in terms of [tex]\( x \)[/tex]:

- First, multiply both sides by 7 to clear the fraction:

[tex]\[ 7x = 3 - y \][/tex]

- Next, isolate [tex]\( y \)[/tex] by subtracting 3 from both sides:

[tex]\[ 7x - 3 = -y \][/tex]

- Then, multiply both sides by -1:

[tex]\[ y = 3 - 7x \][/tex]

5. State the inverse function:

[tex]\[ f^{-1}(x) = 3 - 7x \][/tex]

So, the correct inverse function is:

[tex]\[ f^{-1}(x) = 3 - 7x \][/tex]

Thus, the correct answer is Option D.