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July 19th, 2012, 06:54 AM   #1
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Two Linear Equations

http://tinypic.com/view.php?pic=35lw7xv&s=6 someone can please show me how solve this kind exercises
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July 19th, 2012, 07:12 AM   #2
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Re: Two Linear Equations

It must have taken longer to take and upload that image than merely typing out the equations would have. I'm mobile, or I might just do it myself.

Anywho.
0) google any of the following that you don't understand
1) Write each equation in standard form Ax + By = C
2) use the method of elimination ("systems of equations")
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July 20th, 2012, 03:28 AM   #3
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Doubling the first equation then subtracting the second gives
-10x + 8 - (12x - 7) = -18x + 4y + 12 - (7x + 4y - 9),
i.e., -22x + 15 = -25x + 21,
so x = (21 - 15)/3 = 2.
Replacing x with 2 in either of the given equations leads to y = 3.
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