Graphing Quadratic Equations

A quadratic equation is a polynomial function of degree 2.  It can be written in the form

                        y = ax² + bx + c

where a, b, and c are all real numbers and a ≠ 0.

A quadratic function is often written in the form f(x) = a(x – h)² + k, where a, h and k are real numbers and a ≠ 0.  You may recognize this as the formula for the graph of a parabola.  That is because the graph of every quadratic function is a parabola that either opens up or down.