Many graph experts disagree with Darryl Huff’s argument that the scales of all graphs must begin at zero. I discuss why the rule for bar graphs may differ from that for line graphs.

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.