If the graph of the quadratic function y = a x 2 + b x + c crosses the x -axis, the values of x at the crossing points are the roots or solutions of the equation a x 2 + b x + c = 0.

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An earlier version of this article referred incompletely to the role played by coefficients in the quadratic function, y = ax 2 + bx + c. Both a and b can shift a parabola's axis of symmetry, not ...