document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1027538>Question 1027538</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Sn=1218<BR>\n" );
document.write( "a=8<BR>\n" );
document.write( "difference(b)=5<BR>\n" );
document.write( "how can i find the value of n </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #642744 by </B><A HREF=/tutors/aboutme.mpl?userid=mananth><B>mananth(16946)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=mananth><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=mananth><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=642744\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=Sn+=%28n%2F2%29%282a%2B%28n-1%29d%29 ALIGN=MIDDLE  ALT=\"Sn+=%28n%2F2%29%282a%2B%28n-1%29d%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1218=n%2F2%282%2A8%2B%28n-1%295%29 ALIGN=MIDDLE  ALT=\"1218=n%2F2%282%2A8%2B%28n-1%295%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2436+=+n%2816%2B5n-5%29 ALIGN=MIDDLE  ALT=\"2436+=+n%2816%2B5n-5%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2436+=+16n%2B5n%5E2-5n ALIGN=MIDDLE  ALT=\"2436+=+16n%2B5n%5E2-5n\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "5n^2+11n-2436=0\r<BR>\n" );
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document.write( "solve by formula method\r<BR>\n" );
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document.write( "a=	5	,	b=	11		c=	-2436	<BR>\n" );
document.write( "								<BR>\n" );
document.write( "b^2-4ac=	121	+	48720					<BR>\n" );
document.write( "b^2-4ac=	48841							<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%09sqrt%28%0948841%09%29=%09221%09 ALIGN=MIDDLE  ALT=\"%09sqrt%28%0948841%09%29=%09221%09\"   DISABLED_style= \"max-width:90%; height:auto;\" >			<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x=%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F%282a%29 ALIGN=MIDDLE  ALT=\"x=%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F%282a%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >								<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x1=%28-b%2Bsqrt%28b%5E2-4ac%29%29%2F%282a%29 ALIGN=MIDDLE  ALT=\"x1=%28-b%2Bsqrt%28b%5E2-4ac%29%29%2F%282a%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >								<BR>\n" );
document.write( "x1=(	-11	+	221	)/	10			<BR>\n" );
document.write( "x1=	21.00							<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x2=%28-b-sqrt%28b%5E2-4ac%29%29%2F%282a%29 ALIGN=MIDDLE  ALT=\"x2=%28-b-sqrt%28b%5E2-4ac%29%29%2F%282a%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >								<BR>\n" );
document.write( "x2=(	-11	-221	) /	10				<BR>\n" );
document.write( "x2=	-23.20							<BR>\n" );
document.write( "Ignore negative value								<BR>\n" );
document.write( "n=21<BR>\n" );
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