document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=43849>Question 43849</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Solve the system by substitution.\r<BR>\n" );
document.write( "\n" );
document.write( "x + y = -7\r<BR>\n" );
document.write( "\n" );
document.write( "x - y = 13  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #28865 by </B><A HREF=/tutors/aboutme.mpl?userid=fractalier><B>fractalier(6550)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=fractalier><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=fractalier><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=28865\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> From<BR>\n" );
document.write( "x + y = -7<BR>\n" );
document.write( "x - y = 13<BR>\n" );
document.write( "let us solve the first one for x and substitute it into the second...thus we have<BR>\n" );
document.write( "x = -y - 7 and<BR>\n" );
document.write( "(-y - 7) - y = 13<BR>\n" );
document.write( "-y - 7 - y = 13<BR>\n" );
document.write( "-2y = 20<BR>\n" );
document.write( "y = -10 and then<BR>\n" );
document.write( "x = 3 </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );