Your answer is the third option, x = -2 and x=6
We can see this because the solutions of x^2/2 - 8 = 2x - 2 are going to be where the lines y = x^2/2 - 8 and y = 2x - 2, because this is where the two equations are equal to each other.
Therefore, we can just look on the graph at where the two lines intersect, and see that it happens when x = -2 and x = 6.
I hope this helps!