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Quadratic formula and discriminantTechnique

Technique

Quadratic formula and discriminant

Collect to zero, read a, b, and c, then solve or count

3 min 3 steps

The quadratic formula never fails, as long as you feed it the right a, b, and c. Feeding in the wrong numbers is how my old alibis fell apart.

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The discriminant and quadratic formulaFactCount the solutions, then find them, for any quadratic

Used by

Solve a nonlinear equationTacticLet the form pick the method, then check every root
Solution-count and discriminant analysisTacticCollect everything on one side, then read one sign
Solve a nonlinear systemTacticSubstitute, keep every root, then find each y