document.write( "Question 210670: x-y=15
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Algebra.Com's Answer #159174 by Edwin McCravy(20060)\"\" \"About 
You can put this solution on YOUR website!
\"system%28x-y=15%2Cx%2Ay=700%29\"
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document.write( "Solve the first equation for x:\r\n" );
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document.write( "\"x-y=15\"\r\n" );
document.write( "\"x=15%2By\"\r\n" );
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document.write( "Substitute \"%2815%2By%29\" for \"x\" in the equation \"x%2Ay=700%29\"\r\n" );
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document.write( "\"x%2Ay=700%29\"\r\n" );
document.write( "\"%2815%2By%29%2Ay=700\"\r\n" );
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document.write( "Turn the multiplication around on the left side\r\n" );
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document.write( "\"y%2815%2By%29=700\"\r\n" );
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document.write( "Distribute on the left side\r\n" );
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document.write( "\"15y%2By%5E2=700\"\r\n" );
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document.write( "Get 0 on the right by subtracting 700 from both sides:\r\n" );
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document.write( "\"15y%2By%5E2-700=0\"\r\n" );
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document.write( "Get the left side in descending order of exponents of \"y\"\r\n" );
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document.write( "\"y%5E2%2B15y-700=0\"\r\n" );
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document.write( "Factor:\r\n" );
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document.write( "\"%28y%2B35%29%28y-20%29=0\"\r\n" );
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document.write( "Set each factor equal to 0:\r\n" );
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document.write( "\"y%2B35=0\" gives \"y=-35\"\r\n" );
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document.write( "\"y-20=0\" gives \"y=20\"\r\n" );
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document.write( "To find \"x\" when \"y=-35\", substitute \"%28-35%29\"\r\n" );
document.write( "for \"y\" in \r\n" );
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document.write( "\"x=15%2By\"\r\n" );
document.write( "\"x=15%2B%28-35%29\"\r\n" );
document.write( "\"x=-20\"\r\n" );
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document.write( "So that's one solution: \"%22%28x%2Cy%29%22=%22%28-20%2C-35%29%22\"\r\n" );
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document.write( "To find \"x\" when \"y=20\", substitute \"%2820%29\"\r\n" );
document.write( "for \"y\" in \r\n" );
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document.write( "\"x=15%2By\"\r\n" );
document.write( "\"x=15%2B%2820%29\"\r\n" );
document.write( "\"x=35\"\r\n" );
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document.write( "So the other solution is: \"%22%28x%2Cy%29%22=%22%2835%2C20%29%22\"\r\n" );
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document.write( "Edwin
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