we can simplify it to this:
[tex]y = - 2 {x}^{2} - 12x - 16 [/tex]
so we know it , the intercept in a standard equation of a parabola is C:
[tex]a {x}^{2} + bx + c[/tex]
so the intercept is (-16) and for the vertex use:
x=-b/2a
[tex]x = \frac{12}{ - 4} = - 3 [/tex]
so now put it in the equation and get the y of vertex:
y=-18+36-16=2 ==>vertex(-3,2)
