document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1098559>Question 1098559</A>: <I><SPAN STYLE=\"word-break: break-all;\"> x^2+xy+yz+zx=30 <BR>\n" );
document.write( "y^2+xy+yz+zx=15<BR>\n" );
document.write( "z^2+xy+yz+zx=18 \r<BR>\n" );
document.write( "\n" );
document.write( "find x^2+y^2+z^2 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #712951 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=712951\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> x^2+xy+yz+zx=30 <BR>\n" );
document.write( "y^2+xy+yz+zx=15<BR>\n" );
document.write( "z^2+xy+yz+zx=18 <BR>\n" );
document.write( "a=(xy+yz+zx)<BR>\n" );
document.write( "x^2=30-a<BR>\n" );
document.write( "y^2=15-a<BR>\n" );
document.write( "z^2=18-a<BR>\n" );
document.write( "x^2+y^2+z^2=30-a+15-a+18-a<BR>\n" );
document.write( "x^2+y^2+z^2=30+15+18-3a<BR>\n" );
document.write( "x^2+y^2+z^2=63-3a\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );