Question

Y = a(x-2)(x+4) the graph of the equation in the xy- plane is a parabola with vertex (c,d)

Which of the following is equal to d?

A) -9a
B) -8a
C) -5a
D)-2a

Can you please tell me how to solve it.

Answer 1

A

Explanation:

First set y=0, then solve resulting in y=2,-4, plug those values into the midpoint formula. then you get x=-1, then plug -1 in for x in the equation. so it becomes y=a(-1-2)(-1+4). Solve that and you get y=a(-3)(3), multiply that together and you get -9a