The vertex of a parabola is (-2,-20), and it's y intercept is (0,-12). what is the equation of the parabola?

(y=__x^2 + __x+__)

On plato the answer is:

The equation of the parabola is y = 2x^2 + 8x + (-12).

brainliest?!

Y = a (x + 2) ^2 - 20

to find a:-

when x = 0 y = - 12 so:-

-12 = a (2) ^2 - 20

4a = 20-12 = 8

a = 2

so we have

y = 2 (x + 2) ^2 - 20

y = 2x^2 + 8x + 8 - 20

y = 2x^2 + 8x - 12 is the answer.