document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=985976>Question 985976</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find coordinate of missing endpoint if e is midpoint of df<BR>\n" );
document.write( "f(2,9) e(-1,6) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #606890 by </B><A HREF=/tutors/aboutme.mpl?userid=Cromlix><B>Cromlix(4381)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Cromlix><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=Cromlix><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=606890\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Hi there,<BR>\n" );
document.write( "Using vectors<BR>\n" );
document.write( "DE = EF<BR>\n" );
document.write( "e - d = f - e<BR>\n" );
document.write( "Collect like terms<BR>\n" );
document.write( "-d = f - 2e<BR>\n" );
document.write( "Multiply both sides by -1<BR>\n" );
document.write( "d = 2e - f<BR>\n" );
document.write( "d = 2(-1,6) - (2,9)<BR>\n" );
document.write( "d = (-2,12) - (2,9)<BR>\n" );
document.write( "d = (-4,3)<BR>\n" );
document.write( "This is the missing endpoint.<BR>\n" );
document.write( "Hope this helps :-) </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );