Algebra I: Solving with the quadratic formula
 This is a free lesson from our course in Algebra I In this section, you'll learn another approach to using the quadratic formula. If the left hand side of a given equation ax2 + bx + c = 0 cannot be factorized easily into the product of a pair of binomials, then it can be solved by using the quadratic formula x = {-b  (b2 - 4ac)}/2a and it'll have two roots. For example, if you use the quadratic formula to solve equation x2 + 2x + 7, you get two roots x = -1 2 2. There are some quadratics (most of them, actually) that you can't solve by factoring. But the Quadratic Formula will always work, whether the quadratic was factorable or not.(More text below video...)
Other useful lessons:
 Solve 2nd order polynomial by factoring Solution and discriminant in the quadratic formula Factoring by grouping
(Continued from above) For example, use the Quadratic Formula to solve x2 � 4x � 8 = 0.
Looking at the coefficients, you see that a = 1, b = �4, and c = �8. Plug them into the Formula, and simplify.
x = -(-4) � (-4)2 � 4(1)(-8) / 2(1)
= 4 � (16 + 32) / 2
= 4 � 48 / 2
= 4 � 4 3 / 2
= 2 � 2 3
= 2(1 � 3)
Then the solution is x = 2(1 � 3).
Winpossible's online math courses and tutorials have gained rapidly popularity since their launch in 2008. Over 100,000 students have benefited from Winpossible's courses... these courses in conjunction with free unlimited homework help serve as a very effective math-tutor for our students.
 - All of the Winpossible math tutorials have been designed by top-notch instructors and offer a comprehensive and rigorous math review of that topic. - We guarantee that any student who studies with Winpossible, will get a firm grasp of the associated problem-solving techniques. Each course has our instructors providing step-by-step solutions to a wide variety of problems, completely demystifying the problem-solving process! - Winpossible courses have been used by students for help with homework and by homeschoolers. - Several teachers use Winpossible courses at schools as a supplement for in-class instruction. They also use our course structure to develop course worksheets.

 Copyright © Winpossible, 2010 - 2011 Best viewed in 1024x768 & IE 5.0 or later version