Question

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 1

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:

`-15=a(-7-(-5))^2+9`

Let's clean that up a bit.

`-15=a(-2)^2+9` 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

`y=-6(x+5)^2+9` which is choice C