Answer:
y = 4(x + 2)^2 - 20.
or in standard form it is
y = 4x^2+ 16x - 4.
Step-by-step explanation:
The equation in vertex form will be:
y = a(x + 2)^2 - 20 where a is some constant.
The y-intercept is (0, -12) so:
-12 = a(0 + 2) - 20
2a = -12 + 20 = 8
a = 4.