document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=757230>Question 757230</A>: <I><SPAN STYLE=\"word-break: break-all;\"> What is the sum of the first 45 terms of the following sequence?\r<BR>\n" );
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document.write( "20, 18, 16, . . . </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #460707 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=460707\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> What is the sum of the first 45 terms of the following sequence? <BR>\n" );
document.write( "20, 18, 16, . . .<BR>\n" );
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document.write( "a = 20<BR>\n" );
document.write( "d = -2<BR>\n" );
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document.write( "S(n) = (n/2)(a+a(n))<BR>\n" );
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document.write( "a(n) = a + (n-1)d<BR>\n" );
document.write( "a(45) = 20 + 44*-2 = 20-88 = -68<BR>\n" );
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document.write( "S(45) = (45/2)(20 - 68)<BR>\n" );
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document.write( "= 22.5(-48)<BR>\n" );
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document.write( "= -1080<BR>\n" );
document.write( "===============<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( "===============<BR>\n" );
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