document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=684256>Question 684256</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find n when nC2 = 10. I know the answer but need to show how to work it out. \r<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "\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 #424006 by </B><A HREF=/tutors/aboutme.mpl?userid=MathLover1><B>MathLover1(20850)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=MathLover1><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=MathLover1><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=424006\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\">  	\r<BR>\n" );
document.write( "\n" );
document.write( "when you have a question like <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=nC2=10 ALIGN=MIDDLE  ALT=\"nC2=10\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "to solve for <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n ALIGN=MIDDLE  ALT=\"n\"   DISABLED_style= \"max-width:90%; height:auto;\" >, you can do it this way:\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n%28n-1%29%28n-2%29%2F2%21%28n-2%29%21+=+10 ALIGN=MIDDLE  ALT=\"n%28n-1%29%28n-2%29%2F2%21%28n-2%29%21+=+10\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n%28n-1%29%2F2+=+10 ALIGN=MIDDLE  ALT=\"n%28n-1%29%2F2+=+10\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n%28n-1%29+=+20 ALIGN=MIDDLE  ALT=\"n%28n-1%29+=+20\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n%5E2-n-20=0 ALIGN=MIDDLE  ALT=\"n%5E2-n-20=0\"   DISABLED_style= \"max-width:90%; height:auto;\" >....replace <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-n ALIGN=MIDDLE  ALT=\"-n\"   DISABLED_style= \"max-width:90%; height:auto;\" > with <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-5n%2B4n ALIGN=MIDDLE  ALT=\"-5n%2B4n\"   DISABLED_style= \"max-width:90%; height:auto;\" > and factor\r<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n%5E2-5n%2B4n-20=0 ALIGN=MIDDLE  ALT=\"n%5E2-5n%2B4n-20=0\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28n%2B4%29%28n-5%29=0 ALIGN=MIDDLE  ALT=\"%28n%2B4%29%28n-5%29=0\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "solutions:\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "if <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28n%2B4%29=0 ALIGN=MIDDLE  ALT=\"%28n%2B4%29=0\"   DISABLED_style= \"max-width:90%; height:auto;\" > than <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n=-4 ALIGN=MIDDLE  ALT=\"n=-4\"   DISABLED_style= \"max-width:90%; height:auto;\" > or \r<BR>\n" );
document.write( "\n" );
document.write( "if <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28n-5%29=0 ALIGN=MIDDLE  ALT=\"%28n-5%29=0\"   DISABLED_style= \"max-width:90%; height:auto;\" > than <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n=5 ALIGN=MIDDLE  ALT=\"n=5\"   DISABLED_style= \"max-width:90%; height:auto;\" > ......since <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n ALIGN=MIDDLE  ALT=\"n\"   DISABLED_style= \"max-width:90%; height:auto;\" > can’t be negative we use only solution <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n=5 ALIGN=MIDDLE  ALT=\"n=5\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "check:\r<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=nCr=n%21%2F%28%28n-2%29%21%2Ar%21%29 ALIGN=MIDDLE  ALT=\"nCr=n%21%2F%28%28n-2%29%21%2Ar%21%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "given <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r=2 ALIGN=MIDDLE  ALT=\"r=2\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "solve the expression  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=nC2=n%21%2F%28%28n-2%29%21%2A2%21%29 ALIGN=MIDDLE  ALT=\"nC2=n%21%2F%28%28n-2%29%21%2A2%21%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "plug in <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n=5+ ALIGN=MIDDLE  ALT=\"n=5+\"   DISABLED_style= \"max-width:90%; height:auto;\" > \r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5C2=5%21%2F%28%285-2%29%21%2A2%21%29 ALIGN=MIDDLE  ALT=\"5C2=5%21%2F%28%285-2%29%21%2A2%21%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5C2=%285%2A4%2A3%2A2%2A1%29%2F%283%21%2A2%21%29 ALIGN=MIDDLE  ALT=\"5C2=%285%2A4%2A3%2A2%2A1%29%2F%283%21%2A2%21%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5C2=%285%2A4%2A3%2A2%2A1%29%2F%283%2A2%2A1%2A2%2A1%29 ALIGN=MIDDLE  ALT=\"5C2=%285%2A4%2A3%2A2%2A1%29%2F%283%2A2%2A1%2A2%2A1%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5C2=%285%2Across%284%292%2Across%283%2A2%2A1%29%29%2F%28cross%283%2A2%2A1%29%2Across%282%29%2A1%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5C2=5%2A2 ALIGN=MIDDLE  ALT=\"5C2=5%2A2\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5C2=10 ALIGN=MIDDLE  ALT=\"5C2=10\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );