A quadratic function can be written in the form
are real numbers and
. The shape of the graph of a quadratic function is a parabola. A vertical line called the axis of symmetry divides a parabola into two halves that are mirror images, with the highest or lowest point of the parabola called the vertex. Quadratic functions can be graphed as transformations of the parent function
or by using the values of
to identify the vertex and axis of symmetry. If the points in a scatterplot approximate the shape of a parabola, technology can be used to generate a quadratic function that best fits the data.