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Write the equation in vertex form for the parabola with vertex ( 0, - 4 ) and focus ( 0, - 5 ) .

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This parabola is a vertical one, symmetrical about the y-axis. It opens DOWN. We know that because the focus is beneath the vertex.

We need to write this equation in the form y-k = 4p(x-h)^2, where (h,k) is the vertex. p represents the distance between the vertex and the focus, and is
|-4-(-5)|, or 1.

Thus, y-(-4) = 4(1)(x-0)^2, or y+4 = 4x^2.
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