document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1178676>Question 1178676</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find the nth partial sum of the arithmetic sequence.\r<BR>\n" );
document.write( "\n" );
document.write( "an = 2n − x; n = 19 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #808029 by </B><A HREF=/tutors/aboutme.mpl?userid=MathLover1><B>MathLover1(20850)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=MathLover1><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=MathLover1><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=808029\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> \r<BR>\n" );
document.write( "\n" );
document.write( "Find the nth partial sum of the arithmetic sequence.\r<BR>\n" );
document.write( "\n" );
document.write( "given:\r<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=a%5Bn%5D+=+2n+-x ALIGN=MIDDLE  ALT=\"a%5Bn%5D+=+2n+-x\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( " <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n+=+19 ALIGN=MIDDLE  ALT=\"n+=+19\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "the nth partial sum formula of the arithmetic sequence:\r<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=S%5Bn%5D=%28n%2F2%29%2A%282a%5B1%5D%2B%28n-1%29d%29 ALIGN=MIDDLE  ALT=\"S%5Bn%5D=%28n%2F2%29%2A%282a%5B1%5D%2B%28n-1%29d%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "find first term:\r<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=a%5Bn%5D=a%5B1%5D%2Bd%28n-1%29 ALIGN=MIDDLE  ALT=\"a%5Bn%5D=a%5B1%5D%2Bd%28n-1%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "so,  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=a%5B1%5D%2Bd%28n-1%29=+2n+-x ALIGN=MIDDLE  ALT=\"a%5B1%5D%2Bd%28n-1%29=+2n+-x\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "substitute <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n+=+19 ALIGN=MIDDLE  ALT=\"n+=+19\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "=><IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=a%5B1%5D%2Bd%2819-1%29+=+2%2A19+-x ALIGN=MIDDLE  ALT=\"a%5B1%5D%2Bd%2819-1%29+=+2%2A19+-x\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "=><IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=a%5B1%5D%2B18d=+38+-x ALIGN=MIDDLE  ALT=\"a%5B1%5D%2B18d=+38+-x\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "=><IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=a%5B1%5D=++38+-x-18d ALIGN=MIDDLE  ALT=\"a%5B1%5D=++38+-x-18d\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "go to\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=S%5Bn%5D=%28n%2F2%29%2A%282a%5B1%5D%2B%28n-1%29d%29 ALIGN=MIDDLE  ALT=\"S%5Bn%5D=%28n%2F2%29%2A%282a%5B1%5D%2B%28n-1%29d%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >.........substitute <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=a%5B1%5D+ ALIGN=MIDDLE  ALT=\"a%5B1%5D+\"   DISABLED_style= \"max-width:90%; height:auto;\" >and <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=n ALIGN=MIDDLE  ALT=\"n\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=S%5B19%5D=%2819%2F2%29%2A%282%2838+-x-18d%29%2B%2819-1%29d%29 ALIGN=MIDDLE  ALT=\"S%5B19%5D=%2819%2F2%29%2A%282%2838+-x-18d%29%2B%2819-1%29d%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=S%5B19%5D=%2819%2F2%29%2A%2876+-2x-36d%2B18d%29 ALIGN=MIDDLE  ALT=\"S%5B19%5D=%2819%2F2%29%2A%2876+-2x-36d%2B18d%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=S%5B19%5D=%2819%2F2%29%2A%28-18+d+-+2+x+%2B+76%29 ALIGN=MIDDLE  ALT=\"S%5B19%5D=%2819%2F2%29%2A%28-18+d+-+2+x+%2B+76%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=S%5B19%5D=-171d+-+19x+%2B+722 ALIGN=MIDDLE  ALT=\"S%5B19%5D=-171d+-+19x+%2B+722\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );