document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=924391>Question 924391</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Question : evaluate each of the following arithmetic series\r<BR>\n" );
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document.write( "1, -3, -7, ..., -75 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #560835 by </B><A HREF=/tutors/aboutme.mpl?userid=wangsol><B>wangsol(2)</B></A><img src=\"/images/stars/iconNewId_16x16.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=wangsol><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=wangsol><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=560835\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 1, -3, -7, ..., -75\r<BR>\n" );
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document.write( "a1= 1<BR>\n" );
document.write( "a2= -3\r<BR>\n" );
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document.write( "d=-3-1=-4\r<BR>\n" );
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document.write( "an=-75<BR>\n" );
document.write( "n=?\r<BR>\n" );
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document.write( "using the formula:<BR>\n" );
document.write( "an=a1+(n-1)*d<BR>\n" );
document.write( "-75=1+(n-1)*-4<BR>\n" );
document.write( "-75=1-4n+4<BR>\n" );
document.write( "-75=5-4n<BR>\n" );
document.write( "-80=-4n<BR>\n" );
document.write( "n=(-80)/(-4)<BR>\n" );
document.write( "n=20 terms\r<BR>\n" );
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document.write( "1,-3,-7,-11,-15,-19,-23,-27,-31,-35,-39,-43,-47,-51,-55,-59,-63,-67,-71,-75\r<BR>\n" );
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document.write( "d=-4<BR>\n" );
document.write( "1+(-4)=-3<BR>\n" );
document.write( "(-3)+(-4)=-7<BR>\n" );
document.write( "(-7)+(-4)=-11<BR>\n" );
document.write( "(-11)+(-4)=-15<BR>\n" );
document.write( "and so on...<BR>\n" );
document.write( "(-71)+(-4)=-75 </SPAN>\n" );
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