document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=40979>Question 40979</A>: <I><SPAN STYLE=\"word-break: break-all;\"> solve the arithmetic sequence<BR>\n" );
document.write( "a5=-2 and a13=30 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #26419 by </B><A HREF=/tutors/aboutme.mpl?userid=psbhowmick><B>psbhowmick(878)</B></A><img src=\"/images/stars/stars-11.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=psbhowmick><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=psbhowmick><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=26419\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let first term = a, common difference = d.<BR>\n" );
document.write( "Then an = a + (n-1)d<BR>\n" );
document.write( "When n = 6, a6 = -2 = a + 5d<BR>\n" );
document.write( "When n = 13, a13 = 30 = a + 12d<BR>\n" );
document.write( "Thus we have two equations <BR>\n" );
document.write( "a + 5d = -2 ________(1) <BR>\n" );
document.write( "a + 12d = 30________(2)\r<BR>\n" );
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document.write( "Subtracting eqn. (1) from eqn. (2)<BR>\n" );
document.write( "12d - 5d = 30 - (-2)<BR>\n" );
document.write( "or 7d = 32<BR>\n" );
document.write( "or d = 32/7<BR>\n" );
document.write( "So from (1) a = -2 - 5d = -2 - 5(32/7) = -146/7\r<BR>\n" );
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document.write( "The series has first term -146/7 and common difference 32/7 </SPAN>\n" );
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