Posted by **Clair** on Tuesday, December 8, 2009 at 11:38pm.

I need help in finding the vertex of a parabola using an equation in this form: Ax^2 + Bx+C

I have a test on this tomorrow.

For example: 3x^2 +1x - 2

How would I find the vertex in this?

- Math -
**Reiny**, Tuesday, December 8, 2009 at 11:49pm
Unless you are instructed to do it in a certain way, here is the simplest and quickest way:

For any parabola in the form

y + Ax^2 + Bx + C

the x of the vertex is -B/(2A)

so in our case -1/3

You then sub that back into your equation to find the y of the vertex,

for ours ...

y = 3(1/9) + 1/3 - 2 = 2/3 - 2

= -4/3

Let me know if this answers is sufficient.

- Math -
**Clair**, Tuesday, December 8, 2009 at 11:53pm
Thanks!

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