document.write( "Question 1056580: Use elimination to solve each system of equations. I have to show all work and write the answer as an (x,y) ordered.\r
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Algebra.Com's Answer #671671 by ikleyn(52794) $\"\"$ $\"About$

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\n" ); document.write( "Use elimination to solve each system of equations. I have to show all work and write the answer as an (x,y) ordered.\r
\n" ); document.write( "\n" ); document.write( "7x+4y=-4
\n" ); document.write( "5x+8y=28
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document.write( "7x + 4y = -4,      (1)\r\n" );
document.write( "5x + 8y = 28.      (2)\r\n" );
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document.write( "Multiply equation (1) by 5 (both sides).\r\n" );
document.write( "Multiply equation (2) by 7 (both sides). You will get\r\n" );
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document.write( "35x + 20y = -20,   (1')\r\n" );
document.write( "35x + 56y = 196.   (2')\r\n" );
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document.write( "Distract (1) from (2) (both sides). You will get\r\n" );
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document.write( "56y - 20y = 196 - (-20),   (<--- you got a single equation for only one unknown. It is how ELIMINATION method works !)\r\n" );
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document.write( "36y = 216,\r\n" );
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document.write( "y =  = 6.\r\n" );
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document.write( "Thus you just found \"y\".\r\n" );
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document.write( "Then from (1) 7x = -4 - 4y = -4 -4*6 = -28.\r\n" );
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document.write( "x =  = -4.\r\n" );
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document.write( "Answer.  x = -4,  y = 6.\r\n" );
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\n" ); document.write( "\n" ); document.write( "On Elimination method see the lesson\r
\n" ); document.write( "\n" ); document.write( " - Solution of a linear system of two equations in two unknowns by the Elimination method \r
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