how to get a parabola equation from vertex and x intercepts

Question

2 x-int are -5 and -1 and the vertex is (-3,3.5)

Answer 1

y = a(x+1)(x+5)

3.5 = a(-3+1)(-3+5) = a(-2)(2) = -4a

a=3.5/-4 =-7/8=-.875

y = .875(x+1)(x+5)

y= (7/8)(x^2 +6x +5)