Editing Slide rule (section)

====Roots of quadratic equations====
[[Quadratic equations]] of the form <math>ax^2 + bx + c = 0</math> can be solved by first reducing the equation to the form <math>x^2 - px + q = 0</math> (where <math>p = -b/a</math> and <math>q = c/a</math>), and then aligning the index ("1") of the C scale to the value <math>q</math> on the D scale. The cursor is then moved along the rule until a position is found where the numbers on the CI and D scales add up to <math>p</math>. These two values are the roots of the equation.