document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=98227>Question 98227</A>: <I><SPAN STYLE=\"word-break: break-all;\"> My assignment is to solve the system of equations:  3x + 4y+ z = 7, 2y + z = 3, -5x + 3y + 8z = -31\r<BR>\n" );
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document.write( "But it seems unsolveable to me.  I see no way to eliminate any variables.<BR>\n" );
document.write( "What am I missing? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #71410 by </B><A HREF=/tutors/aboutme.mpl?userid=kev82><B>kev82(151)</B></A><img src=\"/images/stars/stars-09.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=kev82><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=71410\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Hi,<br />\r<BR>\n" );
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document.write( "I don't know how you've been taught to do these, but by the sounds of it, it's by subtraction. I'm going to try and eliminate z by using the second equation. Both the first and second equations have a single z in, so if I subtract them, I will cancel the z term.<br />\r<BR>\n" );
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document.write( "(3x+4y+z) - (2y+z) = 7 - 3<BR>\n" );
document.write( "3x+2y = 4<br />\r<BR>\n" );
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document.write( "The third equation has 8 zeds in it. So we need to subtract the second equation 8 times (or subtract 8* the second equation) from the third equatuation to get rid of all the zeds.<br />\r<BR>\n" );
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document.write( "(-5x+3y+8z) - 8(2y+z) = -31 - 8*3<BR>\n" );
document.write( "-5x-13y = -55<BR>\n" );
document.write( "5x+13y = 55<br />\r<BR>\n" );
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document.write( "So there I have eliminated z, can you now either eliminate x or y from these two equations to get the answer?<br />\r<BR>\n" );
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document.write( "Kev </SPAN>\n" );
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