Why don't you look at a similar problem you posted earlier, and try this one?

Don't you think that's a better way to learn how to do the problem, especially when you get it right?

Whatever you do, DO NOT follow the GARBAGE the other person suggested. Just substitute a point, preferably 

and the vertex,  for (x, y) and (h, k), respectively, in the VERTEX form of a parabolic-equation, to get the value of "a."

Then substitute "a" and (h, k) to get the equation, in VERTEX form. 

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