The equation for a parabola can also be written in the "vertex form":
y = a (x - h) ^ 2 + k
In this equation, the vertex of the parabola is the point (h, k).
We have then:
y = a (x - (-5)) ^ 2 + -2
Substituting the given point:
2 = a (-4 - (-5)) ^ 2 + -2
Clearing a:
2 = a-2
a = 4
Answer:
a = 4
option B
