Systems of Linear EquationsSubject: Algebra Problem Date: Thu, 3 Nov 1994 12:39:21 -0600 (CST) From: Steve Gardner It has been some time since I took algebra and my son has asked me the following question: Solve for each system of equations. x y x-y=5 x + 2y = 10 x+2y=7 & 3x + 4y = 8 x+2y = 10 I can't help. He is tuned in to the NET today and needs some help with this and must show his work. Could you possibly help? thx, steve Date: Thu, 3 Nov 1994 14:12:12 -0500 From: Demetri Bonaros Subject: Re: Algebra Problem Hi, Steve. My name is Demetri and I am one of these math-loving College students involved in Dr. Math. Thank you very much for writing to us. I am sure that we can help you with your son's question; the only problem is that we (I and another member of the crew) don't quite understand what these specific equations are [mainly the problem is with the first equation (x y x-y=5)], or how they are organised (in other words, what the two systems are). Still, I can give you a pointer that could help you get started: since this is a simple system of two equations in two unknowns, try solving one of the two equations in terms of one of the unknowns (for example, you could subtract 2y from both sides of the equation x + 2y = 10 to get x = 10 - 2y). What you have now is an expression for x. The next step is to substitute this expression of x in the other equation of the system. Thus, the second equation will now have only one unknown (namely, y). You can solve this equation to find the value of y and then you can take this value and plug it in the expression for x, to find the value of x. If you think you need more help, please don't hesitate to write again. Demetri, Dr. of some sort. Subject: Re: Algebra Problem Date: Thu, 3 Nov 1994 18:24:13 -0600 (CST) From: Steve Gardner Dr. Demetri Math Thanks for the help. I don't know how the problem got jumbled up, I guess it was my typing. I guess I need a typing class. Believe it or not, I could solve the problem. I just wanted Steve, Jr. to see how the NET could help him in School as opposed to just tuning into the Dead Heads every night. He couldn't imagine that someone like you really was out there and willing to help. From time to time he needs a little push. Steve is a good math student but Geometry is giving him fits. Thanks for the help. The encouragement you give these kids is invaluable. I hope Steve continues to communicate. Thx, Steve, Sr. |
Search the Dr. Math Library: |
[Privacy Policy] [Terms of Use]
Ask Dr. Math^{TM}
© 1994- The Math Forum at NCTM. All rights reserved.
http://mathforum.org/dr.math/