What is the vertex, axis of symmetry, the maximum or minimum value, and the range of parabola y=-2x^2-8x+3?

$D = {d}^{2} = {b}^{2} - 4 a c = 64 + 24 = 88 \to d = \pm 2 \sqrt{22}$
$x = - 2 \pm 2 \frac{\sqrt{22}}{-} 4 = - 2 \pm \frac{\sqrt{22}}{2}$