document.write( "Question 34476: Solve by substitution:\r
\n" ); document.write( "\n" ); document.write( "x+y=12
\n" ); document.write( "y=3x
\n" ); document.write( "

Algebra.Com's Answer #20778 by Prithwis(166)\"\" \"About 
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x+y=12
\n" ); document.write( "y=3x\r
\n" ); document.write( "\n" ); document.write( "x+3x=12
\n" ); document.write( "4x=12
\n" ); document.write( "x=3\r
\n" ); document.write( "\n" ); document.write( "3+y=12
\n" ); document.write( "y=9\r
\n" ); document.write( "\n" ); document.write( "(x,y) = (3,9)
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