document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=17066>Question 17066</A>: <I><SPAN STYLE=\"word-break: break-all;\">  Really, expressions involving variables, subtraction: I am trying to solve     <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3y=6x%2B21+and+3y=-4x%2B31 ALIGN=MIDDLE  ALT=\"3y=6x%2B21+and+3y=-4x%2B31\"   DISABLED_style= \"max-width:90%; height:auto;\" >   by subtraction instead of graphing. I have tried 6x+21minus-4x+31 and came up with 2x + -10 which doesn't work for the problem. How would I find he constant for the variables? What steps do I take to solve it correctly? Thank you for the help! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #8301 by </B><A HREF=/tutors/aboutme.mpl?userid=rapaljer><B>rapaljer(4671)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=rapaljer><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=rapaljer><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=8301\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> If as you say, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3y=6x%2B21 ALIGN=MIDDLE  ALT=\"3y=6x%2B21\"   DISABLED_style= \"max-width:90%; height:auto;\" > and <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3y=-4x%2B31 ALIGN=MIDDLE  ALT=\"3y=-4x%2B31\"   DISABLED_style= \"max-width:90%; height:auto;\" >, then <BR>\n" );
document.write( "3y = 3y, so<BR>\n" );
document.write( "6x+21 = -4x + 31\r<BR>\n" );
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document.write( "It would be a nice idea to solve this equation for x, by adding +4x to each side:<BR>\n" );
document.write( "6x + 4x + 21 = -4x + 4x + 31<BR>\n" );
document.write( "10x + 21 = 31\r<BR>\n" );
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document.write( "Next, subtract 21 from each side:<BR>\n" );
document.write( "10x + 21 - 21 = 31 - 21<BR>\n" );
document.write( "10x = 10<BR>\n" );
document.write( "x= 1\r<BR>\n" );
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document.write( "Solve for y next:<BR>\n" );
document.write( "3y = 6x + 21<BR>\n" );
document.write( "3y = 6(1) + 21<BR>\n" );
document.write( "3y = 27<BR>\n" );
document.write( "y= 9\r<BR>\n" );
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document.write( "Solution (1, 9).\r<BR>\n" );
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document.write( "Check:  Use the other equation.<BR>\n" );
document.write( "3y = -4x + 31<BR>\n" );
document.write( "3(9) = -4(1) + 31<BR>\n" );
document.write( "27 = 27<BR>\n" );
document.write( "It checks!!\r<BR>\n" );
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document.write( "R^2 at SCC </SPAN>\n" );
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