Which function is the inverse of [tex]f(x) = 2x + 3[/tex]?

A. [tex]f^{-1}(x) = -\frac{1}{2}x - \frac{3}{2}[/tex]
B. [tex]f^{-1}(x) = \frac{1}{2}x - \frac{3}{2}[/tex]
C. [tex]f^{-1}(x) = -2x + 3[/tex]
D. [tex]f^{-1}(x) = 2x + 3[/tex]



Answer :

To find the inverse of the function [tex]\( f(x) = 2x + 3 \)[/tex], follow these steps:

1. Write the function in terms of [tex]\( y \)[/tex]:
[tex]\[ y = 2x + 3 \][/tex]

2. Interchange [tex]\( x \)[/tex] and [tex]\( y \)[/tex] to find the inverse function:
[tex]\[ x = 2y + 3 \][/tex]

3. Solve for [tex]\( y \)[/tex]:
[tex]\[ x - 3 = 2y \][/tex]
[tex]\[ y = \frac{x - 3}{2} \][/tex]

4. Rewrite [tex]\( y \)[/tex] as [tex]\( f^{-1}(x) \)[/tex]:
[tex]\[ f^{-1}(x) = \frac{x - 3}{2} \][/tex]

Thus, the inverse function is [tex]\( f^{-1}(x) = \frac{x - 3}{2} \)[/tex].

Now, let's compare this with the given options:

- Option 1: [tex]\( f^{-1}(x) = -\frac{1}{2}x - \frac{3}{2} \)[/tex]
- Option 2: [tex]\( f^{-1}(x) = \frac{1}{2}x - \frac{3}{2} \)[/tex]
- Option 3: [tex]\( f^{-1}(x) = -2x + 3 \)[/tex]
- Option 4: [tex]\( f^{-1}(x) = 2x + 3 \)[/tex]

Clearly, the correct option that matches our derived inverse function is:

[tex]\[ f^{-1}(x) = \frac{1}{2}(x - 3) \][/tex]

Simplifying further,

[tex]\[ f^{-1}(x) = \frac{1}{2}x - \frac{3}{2} \][/tex]

So, the correct answer is:

[tex]\[ f^{-1}(x) = \frac{1}{2} x - \frac{3}{2} \][/tex]

Therefore, the correct option is:

[tex]\[ f^{-1}(x) = \frac{1}{2} x - \frac{3}{2} \][/tex]