Answer:
[tex]y = \pm \sqrt{\frac{x+8}{2} }[/tex]
Step-by-step explanation:
When you're writing the inverse equation, switch the position of the x and y and then solve for y.
[tex]x = 2y^{2} - 8 \\2y^{2} = x+8 \\y^{2} = \frac{x+8}{2}\\ y = \pm \sqrt{\frac{x+8}{2} }[/tex]