Quadratic Formula

For a quadratic equation $a{x}^2+bx+c=0$, the roots are given by

$x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$

The discriminant is the part of the quadratic formula underneath the square root symbol:  $b^2-4ac$

The discriminant tells us whether there are two solutions, one solution, or no solutions.