The graph of y = f (x) where f (x) = x 2 is the same as the graph of y = x 2. Writing equations as functions in the form f (x) is useful when applying translations and reflections to graphs.

All quadratic functions have the same type of curved graphs with a line of symmetry. The graph of the quadratic function y = a x 2 + b x + c is a smooth curve with one turning point.