document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=81308>Question 81308</A>: <I><SPAN STYLE=\"word-break: break-all;\"> \"Find the sum of the first 50 terms of the arithmetic series with first term = -1 and fifth term 9.\"\r<BR>\n" );
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document.write( "So far I tried to find d. Then I tried to plug it into a(sub n) = a(sub 1) + (n - 1)d, so that I could find a(sub n). Then I plugged everything into the formula S(sub n) = n/2(a(sub 1) + a(sub n). But I got a number that doesn't look right. If anyone could help me with this, I would very much appreciate it. Thanks. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #58247 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=58247\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> \"Find the sum of the first 50 terms of the arithmetic series with first term = <BR>\n" );
document.write( "-1 and fifth term 9.\"<BR>\n" );
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document.write( "a(1) = -1<BR>\n" );
document.write( "a(5) = -1 + 4d = 9<BR>\n" );
document.write( "4d=9+1<BR>\n" );
document.write( "d=5/2=2.5<BR>\n" );
document.write( "-----------------<BR>\n" );
document.write( "a(50) = -1+49d=-1+49*2.5= 121.5<BR>\n" );
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document.write( "S(50) = (50/2)(-1+121.5)<BR>\n" );
document.write( "=25(120.5)<BR>\n" );
document.write( "=3012.5 <BR>\n" );
document.write( "==========<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
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