document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1185837>Question 1185837</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The number of combinations of n items taken 2 together is 6 larger than the number of combinations of n - 1 items taken 2 together.\r<BR>\n" );
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document.write( "Determine n.\r<BR>\n" );
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document.write( "Not sure how to solve.<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #816699 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13209)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><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=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=816699\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=C%28n%2C2%29=%28%28n%29%28n-1%29%29%2F2 ALIGN=MIDDLE  ALT=\"C%28n%2C2%29=%28%28n%29%28n-1%29%29%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=C%28n-1%2C2%29=%28%28n-1%29%28n-2%29%29%2F2 ALIGN=MIDDLE  ALT=\"C%28n-1%2C2%29=%28%28n-1%29%28n-2%29%29%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "C(n,2) is 6 more than C(n-1,2):<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28%28n%29%28n-1%29%29%2F2=%28%28n-1%29%28n-2%29%29%2F2%2B6 ALIGN=MIDDLE  ALT=\"%28%28n%29%28n-1%29%29%2F2=%28%28n-1%29%28n-2%29%29%2F2%2B6\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n%28n-1%29=%28n-1%29%28n-2%29%2B12 ALIGN=MIDDLE  ALT=\"n%28n-1%29=%28n-1%29%28n-2%29%2B12\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n%5E2-n=n%5E2-3n%2B2%2B12 ALIGN=MIDDLE  ALT=\"n%5E2-n=n%5E2-3n%2B2%2B12\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2n=14 ALIGN=MIDDLE  ALT=\"2n=14\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n=7 ALIGN=MIDDLE  ALT=\"n=7\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "ANSWER: n=7<br><BR>\n" );
document.write( "CHECK: C(7,2)=21; C(6,2)=15. 21 = 15+6<br><BR>\n" );
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