document.write( "Question 1128391: what are the coordinates of 5x+20y=100 and x+3y=15
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Algebra.Com's Answer #744858 by MathLover1(20855)\"\" \"About 
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\n" ); document.write( "\"5x%2B20y=100\" ...eq.1.....simplify, both sides divide by \"5\"
\n" ); document.write( "\"x%2B3y=15\".......eq.2
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\n" ); document.write( "\"x%2B4y=20\" ...eq.1
\n" ); document.write( "\"x%2B3y=15\".......eq.2
\n" ); document.write( "---------------------------subtract eq.2 from eq.1\r
\n" ); document.write( "\n" ); document.write( "\"x%2B4y-%28x%2B3y%29=20-15\"\r
\n" ); document.write( "\n" ); document.write( "\"x%2B4y-x-3y=5\"\r
\n" ); document.write( "\n" ); document.write( "\"y=5\"\r
\n" ); document.write( "\n" ); document.write( "go back to \"x%2B3y=15\".......eq.2, substitute \"y\" value\r
\n" ); document.write( "\n" ); document.write( "\"x%2B3%2A5=15\"\r
\n" ); document.write( "\n" ); document.write( "\"x%2B15=15\"\r
\n" ); document.write( "\n" ); document.write( "\"x=15-15\"\r
\n" ); document.write( "\n" ); document.write( "\"x=0\"\r
\n" ); document.write( "\n" ); document.write( "=> intersection point of these two lines is at (\"0\",\"5\")\r
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