View more at http://www.MathAndScience.com. In this lesson, you will learn about the quadratic formula in algebra. Specifically, we will learn that the terms under the radical are known as the discriminant and can be used to predict ahead of time what the roots of the quadratic will look like. If the discriminant is positive, then we expect two real roots. If the discriminant is negative, then we expect two complex conjugate roots. If the discriminant is zero, we expect a double root along the x-axis.