Cool Math
Coolmath: Solving Quadratics Recap
This CoolMath resource reviews the ways to solve quadratic equations: factoring, finding square roots, and using the quadratic formula.
National Council of Teachers of Mathematics
The Math Forum: Quadratic Formulas, Equations, Parabolas
Dr. Math here at the Math Forum, in a reply to a student question, helps find the vertex and coordinates of the parabola. The information is somewhat brief, but factual, and worth checking out.