The graph of the quadratic function y = a x 2 + b x + c has a minimum turning point when a> 0 and a maximum turning point when a a <0. The turning point lies on the line of symmetry.

Translations parallel to the y-axis If f (x) = x 2, then f (x) + a = x 2 + a. Here we are adding a to the whole function. The addition of the value a represents a vertical translation in the graph.