document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=153430>Question 153430</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/0028243145/algebrahomeworkh>Advanced Mathematical Concepts</A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> I need help in completing the problem. I need help on starting the problem after I set it up as an augmented matrix. It would be great if I could get it step-by-step: 2x+6y+8z=5; -2x+9y-12z=-1; 4x+6y-4z=3. Thanks a lot! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #112931 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=112931\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\">  2x+6y+8z =5<BR>\n" );
document.write( "-2x+9y-12z=-1<BR>\n" );
document.write( " 4x+6y-4z =3<BR>\n" );
document.write( "--------------------<BR>\n" );
document.write( "+2...+6...+8....+5<BR>\n" );
document.write( "-2...+9...-12...-1<BR>\n" );
document.write( "+4...+6...-4....+3<BR>\n" );
document.write( "-------------------------<BR>\n" );
document.write( "Add 1st to 2nd to get: <BR>\n" );
document.write( "+2...+6...+8....+5<BR>\n" );
document.write( "+0...+15..-4....+4<BR>\n" );
document.write( "+4...+6...-4....+3<BR>\n" );
document.write( "------------------------<BR>\n" );
document.write( "Add -2 times the 1st to the 3rd to get:<BR>\n" );
document.write( "+2...+6...+8....+5<BR>\n" );
document.write( "+0...+15..-4....+4<BR>\n" );
document.write( "+0...-6..-20....-7<BR>\n" );
document.write( "-----------------------<BR>\n" );
document.write( "Add 3rd to 1st to get:<BR>\n" );
document.write( "+2...+0...-12...-2<BR>\n" );
document.write( "+0...+15..-4....+4<BR>\n" );
document.write( "+0...-6..-20....-7<BR>\n" );
document.write( "--------------------<BR>\n" );
document.write( "Divide thru equation 3 by -6:<BR>\n" );
document.write( "+2...+0...-12...-2<BR>\n" );
document.write( "+0...+15..-4....+4<BR>\n" );
document.write( "+0...+1..+10/3..+7/6<BR>\n" );
document.write( "--------------------<BR>\n" );
document.write( "Add -15 time 3rd to the 2nd to get:<BR>\n" );
document.write( "+2...+0...-12...-2<BR>\n" );
document.write( "+0...+0...-54...-13.5<BR>\n" );
document.write( "+0...+1..+10/3..-7/6<BR>\n" );
document.write( "------------------------<BR>\n" );
document.write( "Solve the 2nd equation for z:<BR>\n" );
document.write( "-54z = -13.5<BR>\n" );
document.write( "z = 0.25 or 1/4<BR>\n" );
document.write( "---------------------<BR>\n" );
document.write( "Substitute z = 1/4 into the 3rd equation to solve for \"y\":<BR>\n" );
document.write( "y +(10/3)(1/4) = -7/6<BR>\n" );
document.write( "y + (5/6) = -7/6<BR>\n" );
document.write( "y = -2<BR>\n" );
document.write( "------------------<BR>\n" );
document.write( "Substitute z = 1/4 into the 1st equation to solve for \"x\"<BR>\n" );
document.write( "2x -12*(1/4) = -2<BR>\n" );
document.write( "2x - 3 = -2<BR>\n" );
document.write( "2x = 1<BR>\n" );
document.write( "x = 1/2<BR>\n" );
document.write( "----------------<BR>\n" );
document.write( "Final solution:<BR>\n" );
document.write( "x = 1/2<BR>\n" );
document.write( "y = -2<BR>\n" );
document.write( "z = 1/4<BR>\n" );
document.write( "===============<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. \r<BR>\n" );
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document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
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document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );