What is the equation of the parabola with vertex (3, -20) and that passes through the points (7, 12)

Answer 1

since we know the vertex is (3,-20)
we can start with

y = a(x-3)^2 - 20

plug in the other point (7,12)
12 = a(4)^2 - 20
32 = 16a
a=2

y = 2(x-3)^2 - 20