The discriminant is the number under the square root of the quadratic formula
[tex]x = \frac{-b\pm\sqrt{b^2-4ac}}{2a}[/tex]
The discriminant formula is [tex]D = b^2-4ac[/tex]
If D = 0, then the whole square root portion is 0 meaning we end up with the solution [tex]x = -\frac{b}{2a}[/tex]
