Answer
$$ (-4,18)$$
Work Step by Step
Completing the square in order to write the equation in the form $a(x-h)^2+k$, we find:
$$-\left(x^2+8x-2+4^2-4^2\right) \\ -\left(\left(x+4\right)^2-2-4^2\right) \\ -\left(x+4\right)^2+18$$
The vertex is $(h,k)$, so we see that the vertex is:
$$ (-4,18)$$
