document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=945097>Question 945097</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Determine the number of terms n in each arithmetic series.\r<BR>\n" );
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document.write( "Problem 1: a1= 4, d = 7, Sn= 228 \r<BR>\n" );
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document.write( "Problem 2: (&#8722;2) + (&#8722;12) + (&#8722;22) + (&#8722;32)..., Sn= &#8722;224 \r<BR>\n" );
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document.write( "These problems stumped me...thanks in advance for your time and effort, I appreciate the help! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #576280 by </B><A HREF=/tutors/aboutme.mpl?userid=nerdybill><B>nerdybill(7384)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nerdybill><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=nerdybill><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=576280\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Both problems require the formula to find the nth term of an arithmetic sequence:<BR>\n" );
document.write( "Sn = A1 + (n-1)d<BR>\n" );
document.write( "where<BR>\n" );
document.write( "Sn is \"sum of n terms\"<BR>\n" );
document.write( "A1 is the first term<BR>\n" );
document.write( "n is the number of terms<BR>\n" );
document.write( "d is the distance<BR>\n" );
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document.write( "Problem 1: a1= 4, d = 7, Sn= 228 <BR>\n" );
document.write( "Sn = A1 + (n-1)d<BR>\n" );
document.write( "substitute the values given from the problem:<BR>\n" );
document.write( "228 = 4 + (n-1)7<BR>\n" );
document.write( "228 = 4 + 7n-7<BR>\n" );
document.write( "228 = 7n-3<BR>\n" );
document.write( "231 = 7n<BR>\n" );
document.write( "33 = n<BR>\n" );
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document.write( "Problem 2: (&#8722;2) + (&#8722;12) + (&#8722;22) + (&#8722;32)..., Sn= &#8722;224 <BR>\n" );
document.write( "distance (d) is:<BR>\n" );
document.write( "-12 - (-2) = -12 + 2 = -10<BR>\n" );
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document.write( "Sn = A1 + (n-1)d<BR>\n" );
document.write( "substitute the values given from the problem:<BR>\n" );
document.write( "-224 = -4 + (n-1)-10<BR>\n" );
document.write( "-224 = -4 + -10n+10<BR>\n" );
document.write( "-224 = -10n+6<BR>\n" );
document.write( "-230 = -10n<BR>\n" );
document.write( "23 = n\r<BR>\n" );
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