National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Graphing Parabolas
Dr. Math helps a student with the plotting and with finding the vertex and line of symmetry of a parabola.
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.