document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=896858>Question 896858</A>: <I><SPAN STYLE=\"word-break: break-all;\"> need to explain how to use matrix equation to show that lines represented by y=-3x+4 and y=-4x-8 intersect </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #543841 by </B><A HREF=/tutors/aboutme.mpl?userid=richwmiller><B>richwmiller(17219)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=richwmiller><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=richwmiller><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=543841\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> y=-3x+4 and y=-4x-8<BR>\n" );
document.write( "first put them in order <BR>\n" );
document.write( "x+y=b\r<BR>\n" );
document.write( "\n" );
document.write( "3x+y=4<BR>\n" );
document.write( "4x+y=-8\r<BR>\n" );
document.write( "\n" );
document.write( "3,1,4<BR>\n" );
document.write( "4,1,-8<BR>\n" );
document.write( "A solution to these equations is the intersection of the lines\r<BR>\n" );
document.write( "\n" );
document.write( "3,1,4<BR>\n" );
document.write( "4,1,-8\r<BR>\n" );
document.write( "\n" );
document.write( "divide row 1 by 3<BR>\n" );
document.write( "1,1/3,4/3<BR>\n" );
document.write( "4,1,-8\r<BR>\n" );
document.write( "\n" );
document.write( "add  down (-4) *row 1 to row 2<BR>\n" );
document.write( "1,1/3,4/3<BR>\n" );
document.write( "0,-1/3,-40/3\r<BR>\n" );
document.write( "\n" );
document.write( "divide row 2 by -1/3<BR>\n" );
document.write( "1,1/3,4/3<BR>\n" );
document.write( "0,1,40\r<BR>\n" );
document.write( "\n" );
document.write( "We now have the value for the last variable.<BR>\n" );
document.write( "We will work our way up and get the other solutions.\r<BR>\n" );
document.write( "\n" );
document.write( "add up  (-1/3) *row 2 to row 1<BR>\n" );
document.write( "1,0,-12<BR>\n" );
document.write( "0,1,40\r<BR>\n" );
document.write( "\n" );
document.write( "final<BR>\n" );
document.write( "1,0,-12<BR>\n" );
document.write( "0,1,40\r<BR>\n" );
document.write( "\n" );
document.write( "1,0,-12<BR>\n" );
document.write( "0,1,40<BR>\n" );
document.write( "\"-12\",\"40\"<BR>\n" );
document.write( "(-12,40)\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );