document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=282189>Question 282189</A>: <I><SPAN STYLE=\"word-break: break-all;\"> How do I solve for this using substitution. <BR>\n" );
document.write( "5x+8y=18<BR>\n" );
document.write( "x=6-2y </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #204909 by </B><A HREF=/tutors/aboutme.mpl?userid=oberobic><B>oberobic(2304)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=oberobic><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=204909\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Substitution is done by...well...substitution.<BR>\n" );
document.write( "You use one equation to find a value for 'x'.<BR>\n" );
document.write( "Then you substitute that into the other equation.<BR>\n" );
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document.write( "5x + 8y = 18<BR>\n" );
document.write( "x = 6 -2y<BR>\n" );
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document.write( "So the second equation is a easy substitution candidate into the first equation.<BR>\n" );
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document.write( "5(6-2y) +8y = 18<BR>\n" );
document.write( "30 -10y +8y = 18<BR>\n" );
document.write( "30 -2y = 18<BR>\n" );
document.write( "-2y = -12<BR>\n" );
document.write( "y = 6<BR>\n" );
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document.write( "Now substitute back to find 'x'.<BR>\n" );
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document.write( "x = 6 -2(y)<BR>\n" );
document.write( "x = 6 -2(6)<BR>\n" );
document.write( "x = 6 -12<BR>\n" );
document.write( "x = -6<BR>\n" );
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document.write( "Check by plugging these values into the other equation to ensure they're right.<BR>\n" );
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document.write( "5x + 8y = 18<BR>\n" );
document.write( "5(-6) + 8(6) = 18??<BR>\n" );
document.write( "-30 +48 = 18<BR>\n" );
document.write( "Correct!<BR>\n" );
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document.write( "Answer:<BR>\n" );
document.write( "x = -6<BR>\n" );
document.write( "y = 6<BR>\n" );
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document.write( "Done. </SPAN>\n" );
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