September 10, 2009
No CommentsHow to Solve Quadratic Equations by Factoring
Description
This video shows how to factor quadratic equations. One sample problem is provided and worked through to give a clear explanation of the process.
Overview
A quadratic equation is probably the most well-known type of math problem, following the form ax^2 + bx + c = 0. Most people already know one way of solving these types of equations – the quadratic formula. But the quadratic formula is only one of 3 methods that can be used. The method discussed here is factoring. Factoring is what you call changing a trinomial (a quadratic equation) into two binomials. It is like a reverse method of FOIL. Since you starting out with an x^2 term, the first term in both of your binomials will be x. Now, you need to find the second terms for each of your binomials. You do this by looking for two numbers. These two numbers, when added, must equal the number in the middle term, and when multiplied, they must equal the number in the last term. You can use two negative, two positives, or two negatives and a positive. Let\’s say your numbers end up being -3 and 7. Then your binomials will be (x – 3)(x + 7). It doesn\’t matter if you put the 7 first or the 3 first. To solve, you set each part equal to 0. This means you will have x – 3 = 0 and x + 7 = 0. Then solve for x. Factoring is not possible for all quadratic equations, but it is easier than using the other methods if you think your equation can be factored.
