Solve Using EliminationDate: 01/24/2001 at 21:17:57 From: eva kandler Subject: Algebra Solve by using elimination, and check solutions: x + 6y = 20 x + 2y = 12 Date: 01/26/2001 at 12:37:25 From: Doctor Alicia Subject: Re: Algebra Hi Eva, To solve by elimination, think of your equations in this fashion: If I know that a = b, and that c = d, then it must be true that a - c = b - d because I can subtract the same thing from both sides of an equation, and c and d are the same thing, because they're equal. So given something like: a b | | x + 6y = 20 x + 2y = 12 | | c d I feel confident in writing: a - c = b - d (x + 6y) - (x + 2y) = 20 - 12 So now what? Distribute the negative sign: x + 6y - x - 2y = 20 - 12 Combine like terms: 4y = 8 Divide both sides by 4: y = 2 Plug y = 2 back into either of the original equation and solve for x: [x + 6(2)] - [x + 2(2)] = 20 I hope this helps. Write back if you have any further questions. - Doctor Alicia, The Math Forum http://mathforum.org/dr.math/ |
Search the Dr. Math Library: |
[Privacy Policy] [Terms of Use]
Ask Dr. Math^{TM}
© 1994-2013 The Math Forum
http://mathforum.org/dr.math/