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.

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 ...

Where a changes the width of the curve, a and b shift the axis of symmetry to the left or right, and c slides the curve up or down. The quadratic formula learned by generations of math students is ...