Answer:
a = 4
Step-by-step explanation:
1- We are given that:
zeroes of the parabola are -5 and -3, this means that the factors of the parabola are (x+5) and (x+3)
Therefore:
The general equation of the parabola is:
y = a(x+3)(x+5)
2- We are given that:
point (0,60) lies on the parabola.
To get the value of a, we will substitute with the given point in the equation of the parabola and solve for a as follows:
y = a(x+3)(x+5)
60 = a(0+3)(0+5)
60 = a(3)(5)
60 = 15a

This means that, the equation of the parabola is:
y = 4(x+3)(x+5)
Hope this helps :)