### Sum and Product of Roots Formula - YourTeacher.com

For a complete lesson on the sum and product of roots formula, go to http://www.yourteacher.com - 1000+ online math lessons featuring a personal math teacher inside every lesson! In this lesson, students learn the sum and product of roots formula, which states that if the roots of a quadratic equation are given, the quadratic equation can be written as 0 = x^2 -- (sum of roots)x + (product of roots). For example, to write a quadratic equation that has the given roots --9 and 4, the first step is to find the sum and product of the roots. Since the sum of the roots is --5, and the product of the roots is --36, the quadratic equation can be written as 0 = x^2 -- (-5)x + (-36), which simplifies to 0 = x^2 + 5x -- 36.

Length:
03:54