document.write( "Question 118576: x=-4y
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Algebra.Com's Answer #86695 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
Start with the given system\r
\n" ); document.write( "\n" ); document.write( "\"3x%2B2y=20\"
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\n" ); document.write( "\n" ); document.write( "\"3%28-4y%29%2B2y=20\" Plug in \"x=-4y\" into the first equation. In other words, replace each \"x\" with \"-4y\". Notice we've eliminated the \"x\" variables. So we now have a simple equation with one unknown.\r
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\n" ); document.write( "\n" ); document.write( "\"-12y%2B2y=20\" Multiply\r
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\n" ); document.write( "\n" ); document.write( "\"-10y=20\" Combine like terms on the left side\r
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\n" ); document.write( "\n" ); document.write( "\"y=%2820%29%2F%28-10%29\" Divide both sides by -10 to isolate y\r
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\n" ); document.write( "\n" ); document.write( "\"y=-2\" Divide\r
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\n" ); document.write( "\n" ); document.write( "Now that we know that \"y=-2\", we can plug this into \"x=-4y\" to find \"x\"\r
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\n" ); document.write( "\n" ); document.write( "\"x=-4%28-2%29\" Substitute \"-2\" for each \"y\"\r
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\n" ); document.write( "\n" ); document.write( "\"x=8\" Simplify\r
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\n" ); document.write( "\n" ); document.write( "So our answer is \"x=8\" and \"y=-2\"
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