And when you remember that the graph of a quadratic function is a parabola, this makes a lot of sense. Every parabola has an axis of symmetry that splits the parabola into two mirror-image pieces. In ...

Sketching a quadratic graph using factors If a quadratic equation can be factorised, the factors can be used to find where the graph crosses the x -axis.

Finding roots graphically When the graph of y = a x 2 + b x + c is drawn, the solutions to the equation are the values of the x-coordinates of the points where the graph crosses the x -axis.