Which equation is the inverse of [tex]$y = 2x^2 - 8$[/tex]?

A. [tex]$y = \pm \sqrt{\frac{x + 8}{2}}$[/tex]

B. [tex][tex]$y = \frac{\pm \sqrt{x + 8}}{2}$[/tex][/tex]

C. [tex]$y = \pm \sqrt{\frac{x}{2} + 8}$[/tex]

D. [tex]$y = \frac{\pm \sqrt{x}}{2} + 4$[/tex]



Answer :

To find the inverse of the function [tex]\( y = 2x^2 - 8 \)[/tex], we can follow these steps:

1. Switch [tex]\(x\)[/tex] and [tex]\(y\)[/tex]: Start by replacing [tex]\(y\)[/tex] with [tex]\(x\)[/tex] and [tex]\(x\)[/tex] with [tex]\(y\)[/tex] in the equation. This gives us:
[tex]\[ x = 2y^2 - 8 \][/tex]

2. Solve for [tex]\(y\)[/tex]:
- First, isolate the term with [tex]\(y\)[/tex] on one side. Add 8 to both sides of the equation:
[tex]\[ x + 8 = 2y^2 \][/tex]
- Next, divide both sides by 2 to get:
[tex]\[ \frac{x + 8}{2} = y^2 \][/tex]
- Now, take the square root of both sides. Remember that taking the square root introduces both the positive and negative roots:
[tex]\[ y = \pm \sqrt{\frac{x + 8}{2}} \][/tex]

Thus, the inverse function of [tex]\( y = 2x^2 - 8 \)[/tex] is:
[tex]\[ y = \pm \sqrt{\frac{x + 8}{2}} \][/tex]

Among the given choices, this corresponds to the first option:
[tex]\[ y = \pm \sqrt{\frac{x + 8}{2}} \][/tex]

So, the correct answer is:
[tex]\[ 1 \quad y = \pm \sqrt{\frac{x + 8}{2}} \][/tex]