The Discriminant (Jump to: Lecture | Video )

The Quadratic Formula
The Quadratic Formula is a method for solving quadratic equations.

The Discriminant
The Discriminant tells you how many real roots your quadratic equation has.

If the discriminant is:

Positive, you have 2 real roots.

Zero, you have 1 real root.

Negative, you have 0 real roots(no solution).