quadratic formula
- It gives solution of a quadratic equation $$ x_{1,2} = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}. $$
- Values of $a$, $b$, $c$ are from quadratic equation.
- There might be no real-number solutions.
Elizabeth Stapel, "The Quadratic Formula Explained", Purplemath, 1 Oct 1999, https://www.purplemath.com/modules/quadform.htm
[20241222].