document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=468668>Question 468668</A>: <I><SPAN STYLE=\"word-break: break-all;\"> How do I solve the system in matrices?:<BR>\n" );
document.write( "{x+y=2<BR>\n" );
document.write( "{x-y=-4<BR>\n" );
document.write( "{2x+y=1\r<BR>\n" );
document.write( "\n" );
document.write( "and<BR>\n" );
document.write( "{x+y=4<BR>\n" );
document.write( "{2x-y=2 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #321571 by </B><A HREF=/tutors/aboutme.mpl?userid=Alan3354><B>Alan3354(69443)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Alan3354><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=Alan3354><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=321571\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> How do I solve the system in matrices?:<BR>\n" );
document.write( "{x+y=2<BR>\n" );
document.write( "{x-y=-4<BR>\n" );
document.write( "{2x+y=1<BR>\n" );
document.write( "You have 3 eqns in x & y ??<BR>\n" );
document.write( "{x+y=2<BR>\n" );
document.write( "{x-y=-4<BR>\n" );
document.write( "---------<BR>\n" );
document.write( "2x = -2<BR>\n" );
document.write( "x = -1<BR>\n" );
document.write( "-------<BR>\n" );
document.write( "y = 3<BR>\n" );
document.write( "---------<BR>\n" );
document.write( "You can solve an augmented 2 by 2 matrix with any 2 of the 3 equations.<BR>\n" );
document.write( "If you assume 0z for each and make it 3 by 3, z is undefined anyway.<BR>\n" );
document.write( "------------------<BR>\n" );
document.write( "and<BR>\n" );
document.write( "{x+y=4<BR>\n" );
document.write( "{2x-y=2<BR>\n" );
document.write( "----------<BR>\n" );
document.write( "|1 1 -4|<BR>\n" );
document.write( "|2-1 -2|<BR>\n" );
document.write( "Det = -1-2 = -3<BR>\n" );
document.write( "---------<BR>\n" );
document.write( "Dx = -2 -4 = -6<BR>\n" );
document.write( "x = Dx/Det = 2<BR>\n" );
document.write( "----------<BR>\n" );
document.write( "-Dy = -2 + 8 = 6<BR>\n" );
document.write( "y = -6/Det = 2<BR>\n" );
document.write( "----------------<BR>\n" );
document.write( "x = 2<BR>\n" );
document.write( "y = 2<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );