Step-by-step explanation:
if parabola has a vertex not in x-axis, it should have 2 x intercept
x-vertex = -2
first x intercept = 3
second x intercept should -7
so the equation will like this
y = a(x-x1)(x-x2)
y = a (x-3)(x+7)
y = a(x² + 4x - 21)
5 = a((-2)² + 4(-2) - 21)
5 = a(4 - 8 - 21)
5 = a(-25)
a = 5/(-25)
a = -1/5
then the equation is
y = (-1/5)(x² - 4x - 21)
or you can write as
y = -x²/5 + 4x/5 + 21/5
or as this one
5y = -x² + 4x + 21