The discriminate of any equation in any degree plays an important role in determining the roots of that equation. In case of a quadratic equation with a positive discriminate, the roots are real while a 0 discriminate indicates a single real root. A negative discriminant indicates imaginary (complex number format) roots. As shown in the video (along with a plot of the aforesaid equation), the discriminant of the equation a(x^2) + bx + c is (b^2) - 4ac. This is a straightforward way of calculating the discriminant. This same discriminant can be used to even find the roots of the quadratic equation.