document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=107332>Question 107332</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/0321279220/algebrahomeworkh>Introductory and Intermediate Algebra</A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> I'm not really clear on how to set up this type of problem. Any insight would be greatly appreciated. x+y=12<BR>\n" );
document.write( "                         y=3x </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #78125 by </B><A HREF=/tutors/aboutme.mpl?userid=ptaylor><B>ptaylor(2198)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ptaylor><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=ptaylor><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=78125\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> x+y=12-------------------eq1<BR>\n" );
document.write( "y=3x----------------------eq2\r<BR>\n" );
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document.write( "I think that substituting \"y=3x\" from eq2 into eq1 is the easiest way to work this problem.  If we do that, we get:\r<BR>\n" );
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document.write( "x+3x=12 or<BR>\n" );
document.write( "4x=12 divide both sides by 4<BR>\n" );
document.write( "x=3<BR>\n" );
document.write( "From eq2:<BR>\n" );
document.write( "y=3x=3*3=9\r<BR>\n" );
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document.write( "So:<BR>\n" );
document.write( "x=3<BR>\n" );
document.write( "and<BR>\n" );
document.write( "y=9\r<BR>\n" );
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document.write( "We could also subtract eq2 from eq1 and we would get:\r<BR>\n" );
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document.write( "x=12-3x  add 3x to both sides\r<BR>\n" );
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document.write( "x+3x=12-3x+3x or<BR>\n" );
document.write( "4x=12  same as before\r<BR>\n" );
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document.write( "CK\r<BR>\n" );
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document.write( "from eq1<BR>\n" );
document.write( "x+y=12<BR>\n" );
document.write( "3+9=12<BR>\n" );
document.write( "12=12<BR>\n" );
document.write( "from eq2<BR>\n" );
document.write( "y=3x<BR>\n" );
document.write( "9=3*3<BR>\n" );
document.write( "9=9\r<BR>\n" );
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document.write( "Hope this helps----ptaylor </SPAN>\n" );
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