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

A. [tex]y = \pm \sqrt{\frac{x + 8}{2}}[/tex]
B. [tex]y = \frac{\pm \sqrt{x + 8}}{2}[/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 \( y = 2x^2 - 8 \), we need to follow a series of steps. Here is the detailed step-by-step solution:

1. Express \( y \) in terms of \( x \):
Given the function:
[tex]\[ y = 2x^2 - 8 \][/tex]

2. Swap \( x \) and \( y \):
To find the inverse, we interchange \( x \) and \( y \):
[tex]\[ x = 2y^2 - 8 \][/tex]

3. Solve for \( y \):
We need to isolate \( y \) on one side. Start by solving the equation for \( y \):
[tex]\[ x = 2y^2 - 8 \][/tex]
Add 8 to both sides:
[tex]\[ x + 8 = 2y^2 \][/tex]
Divide both sides by 2:
[tex]\[ \frac{x + 8}{2} = y^2 \][/tex]
Take the square root of both sides. Remember that taking the square root introduces a plus and minus:
[tex]\[ y = \pm \sqrt{\frac{x + 8}{2}} \][/tex]

4. Verify the solution:
Thus, the inverse functions derived from the original function are:
[tex]\[ y = \sqrt{\frac{x + 8}{2}} \quad \text{and} \quad y = -\sqrt{\frac{x + 8}{2}} \][/tex]

Given these steps and the derived expressions, the correct inverse equations align with the option:
[tex]\[ y= \pm \sqrt{\frac{x}{2} + 8} \][/tex]

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