document.write( "Question 1071877: { y=3x x+2y=-21. Sovle the system by by substitution. Enter your answer as an ordered pair, or type none or infinite. \n" ); document.write( "
Algebra.Com's Answer #686798 by Boreal(15235)\"\" \"About 
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y=3x
\n" ); document.write( "x+2y=21
\n" ); document.write( "substitute
\n" ); document.write( "x+6x=21
\n" ); document.write( "7x=21
\n" ); document.write( "x=3
\n" ); document.write( "y=9
\n" ); document.write( "check
\n" ); document.write( "3+18=21
\n" ); document.write( "(3,9)
\n" ); document.write( " \n" ); document.write( "
\n" );