document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=664824>Question 664824</A>: <I><SPAN STYLE=\"word-break: break-all;\"> what is sum of the first 20 terms if the firs term is 73 and the last term is -101? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #413458 by </B><A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><B>jim_thompson5910(35256)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=413458\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Sn = (n*(a1 + an))/2\r<BR>\n" );
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document.write( "S20 = (20*(73 + -101))/2\r<BR>\n" );
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document.write( "S20 = (20*(-28))/2\r<BR>\n" );
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document.write( "S20 = (-560)/2\r<BR>\n" );
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document.write( "S20 = -280\r<BR>\n" );
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document.write( "So the answer is -280 </SPAN>\n" );
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