document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=270497>Question 270497</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please explain this linear equation:\r<BR>\n" );
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document.write( "If x + y = 15 and x -y = -19 then xy = ?\r<BR>\n" );
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document.write( "Thanks,<BR>\n" );
document.write( "Jesse Evans<BR>\n" );
document.write( "jesseevans@hughes.net </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #198176 by </B><A HREF=/tutors/aboutme.mpl?userid=vleith><B>vleith(2983)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=vleith><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=198176\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Jesse, a word to the wise. Don't use your name or give away your email. OK?\r<BR>\n" );
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document.write( "Now, to solve your question ...<BR>\n" );
document.write( "If x + y = 15 and x -y = -19 then xy = ?<BR>\n" );
document.write( "Solve the two linear eqautions to find the point that they intersect (the point given by (x,y)\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+%2B+y+=+15 ALIGN=MIDDLE  ALT=\"x+%2B+y+=+15\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+-+y+=+-19 ALIGN=MIDDLE  ALT=\"x+-+y+=+-19\"   DISABLED_style= \"max-width:90%; height:auto;\" > let's use elmination. So just add the two equations<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2x++=+-4 ALIGN=MIDDLE  ALT=\"2x++=+-4\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+-2 ALIGN=MIDDLE  ALT=\"x+=+-2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Use x to find y<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+%2B+y+=+15 ALIGN=MIDDLE  ALT=\"x+%2B+y+=+15\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2+%2B+y+=+15 ALIGN=MIDDLE  ALT=\"2+%2B+y+=+15\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y=13 ALIGN=MIDDLE  ALT=\"y=13\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "So the point those two lines have in common is (2,13)\r<BR>\n" );
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document.write( "Given that<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=xy+=+2%2A13+=+26 ALIGN=MIDDLE  ALT=\"xy+=+2%2A13+=+26\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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