document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=131197>Question 131197</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In a round-robin tennis tournament, every player meets every other player exactly once. How many players can participate in a tournament of 45 matches? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #96216 by </B><A HREF=/tutors/aboutme.mpl?userid=scott8148><B>scott8148(6628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=scott8148><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=scott8148><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=96216\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> let x=\"number of players\" __ each player plays x-1 matches BUT a vs b is the same as b vs a<BR>\n" );
document.write( "__ so the number of matches is x(x-1)/2\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "x(x-1)/2=45 __ multiplying by 2 and subtracting 90 __ x^2-x-90=0\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "factoring __ (x+9)(x-10)=0 __ x+9=0 and x-10=0 </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );