SOLUTION: Write a quadratic function in vertex form that has the given vertex and passes through the given point. Vertex (-2, -2) Point (1, -20)

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Question 117604: Write a quadratic function in vertex form that has the given vertex and passes through the given point. Vertex (-2, -2) Point (1, -20)
Answer by solver91311(24713) About Me  (Show Source):
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The vertex form of a parabola's equation is generally expressed as :
y=+a%28x-h%29%5E2%2Bk+ where (h,k) is the vertex.

You are given the vertex (-2-2), so the equation becomes:

y=+a%28x-%28-2%29%29%5E2%2B%28-2%29
y=a%28x%2B2%29%5E2-2

Since the parabola contains the point (1, -20), substitute these values for x and y, and then solve the equation for a:

-20=a%281%2B2%29%5E2-2
-9a=20-2
a=-%2818%2F9%29=-2

Now replace a with the value determined,
y=-2%28x%2B2%29%5E2-2