Write an equation of the parabola in vertex from y=a(x-h)^2 +k that passes through (-7,-15) and has vertex (-5,9).

Answer:
Step-by-step explanation:
We have the work form of the equation, and we also have values for x, y, h, and k. All we need to do is fill those in and solve for a:
[tex]-15=a(-7-(-5))^2+9[/tex]
Let's clean that up a bit.
[tex]-15=a(-2)^2+9[/tex] and
-15 = 4a + 9 and
-24 = 4a so
a = -6
Now we'll fill in the a value along with the h and k to get
[tex]y=-6(x+5)^2+9[/tex] which is choice C