document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1109238>Question 1109238</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 1) the sum of the first 12 of an A.p is -96 and the Sum of  the first 18th term is -252. find the <BR>\n" );
document.write( "(a)common difference and <BR>\n" );
document.write( "(b)the first term\r<BR>\n" );
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document.write( "2) How many terms of an A.p, 5,13,21............ give as sum of 275 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #724285 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=724285\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> sum is (n/2)(a1+an)<BR>\n" );
document.write( "for 12 terms 6(a1+a12)=-96<BR>\n" );
document.write( "for 18 terms 9*(a1+a18)=-252<BR>\n" );
document.write( "a1+a12=-16<BR>\n" );
document.write( "a1+a18=-28<BR>\n" );
document.write( "d=-2 ANSWER<BR>\n" );
document.write( "sum = (n/2)(2a1+(n-1)d)<BR>\n" );
document.write( "=6(2a1+11*-2)=-96<BR>\n" );
document.write( "-16=2a1-22<BR>\n" );
document.write( "2a1=6<BR>\n" );
document.write( "a1=3 ANSWER<BR>\n" );
document.write( "sum = -96=(12/2)(a1+a12)<BR>\n" );
document.write( "-16=3+a12<BR>\n" );
document.write( "a12=-19<BR>\n" );
document.write( "a18=-31<BR>\n" );
document.write( "==================<BR>\n" );
document.write( "there is not an exact number of terms<BR>\n" );
document.write( "5,13,21,29,37,45,53,61,69<BR>\n" );
document.write( "sum=(n/2)(a1+an)<BR>\n" );
document.write( "when n=8 and an=a1+(n-1)8, with difference of 8<BR>\n" );
document.write( "an=5+56=61<BR>\n" );
document.write( "and sum is 4(61) or 244, and the next term isn't 31<BR>\n" );
document.write( " </SPAN>\n" );
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