document.write( "Question 82999: Okay I really need someone's help with this one. Substitution confuses me. I need to solve the system by substitution:\r
\n" ); document.write( "\n" ); document.write( "3x+3y=9
\n" ); document.write( "y=2x-12
\n" ); document.write( "

Algebra.Com's Answer #59558 by checkley75(3666)\"\" \"About 
You can put this solution on YOUR website!
y=2x-12 now substitute (2x-12) for y in the other equation thus:
\n" ); document.write( "3x+3(2x-12)=9
\n" ); document.write( "3x+6x-36=9
\n" ); document.write( "9x=9+36
\n" ); document.write( "9x=45
\n" ); document.write( "x=45/9
\n" ); document.write( "x=5 answer.
\n" ); document.write( "y=2*5-12
\n" ); document.write( "y=10-12
\n" ); document.write( "y=-2 answer.
\n" ); document.write( "proof
\n" ); document.write( "3*5+3*-2=9
\n" ); document.write( "15-6=9
\n" ); document.write( "9=9
\n" ); document.write( "
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