Vertex of a parabola exists at:
[tex]( \frac{-b}{2a},y( \frac{-b}{2a})) [/tex]
b = coefficient of x term = 8
a = coefficient of squared term = 2
So,
[tex] \frac{-b}{2a}= \frac{-8}{4}=-2 [/tex]
and
[tex]y(-2)=2(-2)^{2}+8(-2)+1=-7 [/tex]
Therefore, the vertex occurs at (-2, -7)
So, the correct answer is option C
