Answer:
y = 2(x - 3)² - 20
Explanation:
y = a(x - h)² + k - vertex form of the equation of the parabola with vertex (h, k)
So the equation of the parabola with vertex (3, -20):
y = a(x - 3)² + (-20)
y = a(x - 3)² - 20
The parabola passes through point (7, 12) so if x=7 then y=12
12 = a(7 - 3)² + (-20)
12 +20 = a(4)² - 20 +20
32 = 16a
a = 2
Therefore the equation of the parabola with vertex (3, -20) and that passes through point (7, 12):
y = 2(x - 3)² - 20