M6 · Advanced
Algebra
Quadratic formula
Formula
x = (-b +/- sqrt(b^2 - 4ac)) / 2a
Rule
Solves ax^2 + bx + c = 0. The discriminant b^2 - 4ac tells how many roots.
Example
x^2 - 5x + 6 = 0 -> x = 2 or 3
Tip
Discriminant > 0: two roots, = 0: one, < 0: none.
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Quadratic functions