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 March 20th, 2014, 07:44 AM #1 Newbie   Joined: Mar 2014 Posts: 2 Thanks: 0 Linear equation word problem I am having the most difficult time trying to determine how to set up and solve this word problem, can anyone help? 6.The price of an entertainment system at Electronics One is $220 less than twice the price of the same system at Electronics Two.The difference in price between the system at Electronics One and Electronics Two is$175. Which system of linear equations can be used to determine the price of the system at each store?
 March 20th, 2014, 08:16 AM #2 Senior Member     Joined: Jul 2010 From: St. Augustine, FL., U.S.A.'s oldest city Posts: 12,211 Thanks: 521 Math Focus: Calculus/ODEs Re: Linear equation word problem Let A be the price at Electronics One and B be the price at Electronics Two. Then we may state: $A=2B-220$ $A-B=175$
 March 21st, 2014, 05:19 AM #3 Newbie   Joined: Mar 2014 Posts: 2 Thanks: 0 Re: Linear equation word problem Thank you so much!
 March 21st, 2014, 09:02 AM #4 Senior Member   Joined: Mar 2014 Posts: 112 Thanks: 8 Let A - 2B = -220. If A > B then we have A - B = 175 i.e. B = 395. Plug in this and we get A = 395 + 175 = 570. If A < B then we have B - A = 175 i.e. B = 45. Plug in this and we get A = 45 - 175 = -130. Since it's price A > B is correct.
 March 21st, 2014, 11:21 AM #5 Math Team   Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 14,414 Thanks: 1024 Re: Linear equation word problem -a + 2b = 220 a - b = 175 Add to get b = 395 ; so a = 570 John, why can't we simply stop here?
 March 21st, 2014, 05:52 PM #6 Senior Member   Joined: Mar 2014 Posts: 112 Thanks: 8 Because MarkFL gave us such equation. You probably got it correctly. Now my question is would it still work for B - A = 175? I edited my above post, so incorrect for A < B.
March 22nd, 2014, 05:03 PM   #7
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Quote:
 Originally Posted by the john Let A - 2B = 220.
That's incorrect, so you got incorrect results.

 March 22nd, 2014, 08:21 PM #8 Senior Member   Joined: Mar 2014 Posts: 112 Thanks: 8 Thanks, skipjack. If I read the original post more carefully I should have got A = 2B - 220 i.e. A - 2B = -220.
March 22nd, 2014, 08:47 PM   #9
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Quote:
 Originally Posted by the john Thanks, skipjack. If I read the original post more carefully I should have got A = 2B - 220 i.e. A - 2B = -220.
To the corner for 15 minutes, John! (I'm already there )

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