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

Question

I have a test on this tomorrow.
For example: 3x^2 +1x - 2
How would I find the vertex in this?

Answer 1

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.

Answer 2

Thanks!