document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=72775>Question 72775</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Solve the system by substitution.<BR>\n" );
document.write( "     3x – y = –7<BR>\n" );
document.write( "       x + y = –9<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #52284 by </B><A HREF=/tutors/aboutme.mpl?userid=checkley75><B>checkley75(3666)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=checkley75><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=52284\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> X+Y=-9, X=-Y-9 NOW SUBSTITUTE (-Y-9) FOR X IN THE OTHER EQUATION<BR>\n" );
document.write( "3(-Y-9)-Y=-7<BR>\n" );
document.write( "-3Y-27-Y=-7<BR>\n" );
document.write( "-3Y-Y=-7+27<BR>\n" );
document.write( "-4Y=20<BR>\n" );
document.write( "Y=20/-4<BR>\n" );
document.write( "Y=-5 ANSWER.<BR>\n" );
document.write( "X-5=-9<BR>\n" );
document.write( "X=-9+5<BR>\n" );
document.write( "X=-4 ANSWER.<BR>\n" );
document.write( "PROOF<BR>\n" );
document.write( "3*-4+5=-7<BR>\n" );
document.write( "-12+5=-7<BR>\n" );
document.write( "-7=-7 </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );