# Equation of a parabola

• Feb 22nd 2010, 11:24 PM
lance
Equation of a parabola
Vertex: (0,0); contains (-3,-4) and (-3,4)...
Find the equation.. Please help me or just give me an idea on how to do this problem... Thanks!
• Feb 22nd 2010, 11:39 PM
Prove It
Quote:

Originally Posted by lance
Vertex: (0,0); contains (-3,-4) and (-3,4)...
Find the equation.. Please help me or just give me an idea on how to do this problem... Thanks!

A parabola can be written as

$y = a(x - h)^2 + k$, where $h$ is the $x$ coordinate of the vertex and $k$ is the $y$ coordinate of the vertex.

So so far we know $y = a(x - 0)^2 + 0$

$y = ax^2$.

Now substitute one of the other points and solve for $a$.