document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=861041>Question 861041</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 1)<BR>\n" );
document.write( "Given that for an AP seventh term=43 and second term=91,find the valves of a,d and n.(11).<BR>\n" );
document.write( "2)<BR>\n" );
document.write( " The first term of an AP is -18 and the last term is 115.If the sum of the progression is 970.Find the number of terms in the AP and the common difference. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #518841 by </B><A HREF=/tutors/aboutme.mpl?userid=richwmiller><B>richwmiller(17219)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=richwmiller><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=richwmiller><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=518841\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Already answered the first one, although the answer isn't pretty.\r<BR>\n" );
document.write( "\n" );
document.write( "S = ½(a + an)n<BR>\n" );
document.write( "S = ½(2a + (n-1)d)n<BR>\n" );
document.write( "an = a + (n - 1)d\r<BR>\n" );
document.write( "\n" );
document.write( "970 = ½(-18 + 115)n<BR>\n" );
document.write( "970 = ½(97)n<BR>\n" );
document.write( "10=n/2<BR>\n" );
document.write( "n=20 terms<BR>\n" );
document.write( "133 = (19)d<BR>\n" );
document.write( "d=7 difference </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );