alamama Posted March 24, 2011 Share Posted March 24, 2011 We use MUS. Daughter and I are stuck on lesson 26 & 27. Repeating Factoring of Polynomials (26) and Solving Equations with Factoring. Do you know how to solve these? 4 2 X - 16 2X + 3X = 2 Steve has ex 2 shown this way. I get lost on the red part. 2 2X + 3X=2 2 2X + 3X -2=0 (2X-1)(X+2)=0 Can someone explain this to me? The positive negative thing throws me as well. Thanks for any help you all can give us. Quote Link to comment Share on other sites More sharing options...
Susan C. Posted March 24, 2011 Share Posted March 24, 2011 It didn't come through where I can tell what it is.... Maybe reformat it and post over on the high school board. Quote Link to comment Share on other sites More sharing options...
Mrs Mungo Posted March 24, 2011 Share Posted March 24, 2011 Have you checked out the purple math website? Quote Link to comment Share on other sites More sharing options...
alamama Posted March 24, 2011 Author Share Posted March 24, 2011 It didn't come through where I can tell what it is.... Maybe reformat it and post over on the high school board. Thanks. I will do that. Have you checked out the purple math website? No, but I will head over there soon! Thanks! Quote Link to comment Share on other sites More sharing options...
Martha in GA Posted March 24, 2011 Share Posted March 24, 2011 (edited) It took me a while to figure out what the question was, but I think I figured it out... 2x^2 + 3x = 2 Subtract 2 from both sides to get a quadratic equation that can be factored: 2x^2 + 3x -2 = 0 To get 2x^2, one factor has to be 2x and the other 1x (2x times 1x is 2x^2): (2x )(1x ) = 0 Because the equation has "-2", one factor has to be positive, and the other negative (so -1 and 2, or -2 and 1). To get the middle term to be +3, the +2 has to be multiplied by 2x and the -1 multiplied by 1x (2x*2 + 1x* (-1) = 3x): (2x -1) (1x +2) = 0 I hope that helps. It is kind of hard trying to do this on the board! Edited March 24, 2011 by Martha in GA trying to improve formatting Quote Link to comment Share on other sites More sharing options...
Dana Posted March 24, 2011 Share Posted March 24, 2011 In order to factor, you need to be very good at multiplying two polynomials. Basically, you use trial & error to find factors of the first term and the last term. Then see if the sum or difference of the products gives you the middle term. If you've put in a lot of time with binomial multiplication, you can see better what's going on. Purplemath is good. There are a number of "methods" for factoring. I view it more as a skill and something that you need to practice a lot (maybe with some help being walked through the process) but with first a solid foundation on multiplication. Factoring is pretty important when working with rational expressions and equations, so you do want to get it figured out. Quote Link to comment Share on other sites More sharing options...
alamama Posted March 28, 2011 Author Share Posted March 28, 2011 What is Purplemath? Quote Link to comment Share on other sites More sharing options...
Mrs Mungo Posted March 28, 2011 Share Posted March 28, 2011 What is Purplemath? It is an algebra help website. Did you click on the link? Quote Link to comment Share on other sites More sharing options...
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