Answer:
The answer is C
Step-by-step explanation:
the y-intercept is going through 0 therefore there would be no "b" in the y=mx+b formula

Compare to the vertex form of parabola
So vertex should be at (h,k)=(-2,-1)
Graph attached
As they are vertical angles, their magnitude will be equal.
8x+8 = 2x+38
8x-2x = 38-8
6x = 30
x = 5
So, Your Final Answer would be 5
Hope this helps!