vertex for is
y = a(x - h)^2 + k where (h,k) is the vertex.
so we have
y = a(x - (-2)^2 - 20
y = a(x + 2)^2 - 20
y intercept is (0,-12) so:-
-12 = a(2)^2 - 20
4a = 8
a = 2
y = 2(x + 2)^2 - 20 is the parabola in vertex form Convert to standard form:-
y = 2(x^2 + 4x + 4) - 20
y = 2x^2 + 8x -12 is the answer