Question

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+__)

Answer 1

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.