document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1086752>Question 1086752</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Solve for n: \r<BR>\n" );
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document.write( "S = n/2 (a + l) \r<BR>\n" );
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document.write( "2S = n (2a + 2l) \r<BR>\n" );
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document.write( "2S / 2 = 2an + 2ln / 2 \r<BR>\n" );
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document.write( "S = an + ln \r<BR>\n" );
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document.write( "How do I continue?  Non-homework. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #701003 by </B><A HREF=/tutors/aboutme.mpl?userid=math_helper><B>math_helper(2461)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=math_helper><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=math_helper><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=701003\">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=+S+=+%28n%2F2%29%28a%2Bl%29%29++ ALIGN=MIDDLE  ALT=\"+S+=+%28n%2F2%29%28a%2Bl%29%29++\"   DISABLED_style= \"max-width:90%; height:auto;\" >    <<< Assuming this is what you intended for starting expression, same as S=(n/2)(a+l)<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%28n%2F2%29%28a%2Bl%29+=+S+ ALIGN=MIDDLE  ALT=\"+%28n%2F2%29%28a%2Bl%29+=+S+\"   DISABLED_style= \"max-width:90%; height:auto;\" >      ( Rearranged left and right sides, since we're solving for n let's write it on left. )<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+n%28a%2Bl%29+=+2S ALIGN=MIDDLE  ALT=\"+n%28a%2Bl%29+=+2S\"   DISABLED_style= \"max-width:90%; height:auto;\" >          ( Multiplied both sides by 2. )<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+n+=+2S%2F%28a%2Bl%29+ ALIGN=MIDDLE  ALT=\"+n+=+2S%2F%28a%2Bl%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" >         ( <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+cross%28Multiplied%29+ ALIGN=MIDDLE  ALT=\"+cross%28Multiplied%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" > Divided both sides by a+l.  Done. ) <BR>\n" );
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document.write( "Your 2nd step above has an error:   S = (n/2)(a+l) becomes 2S = n(a+l)  after multiplying both sides by 2, not  2S=n(2a+2l).<BR>\n" );
document.write( "  <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=S++=+%28n%2F2%29%28a%2Bl%29+ ALIGN=MIDDLE  ALT=\"S++=+%28n%2F2%29%28a%2Bl%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2S+=+%282n%2F2%29%28a%2Bl%29%29+ ALIGN=MIDDLE  ALT=\"2S+=+%282n%2F2%29%28a%2Bl%29%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+2S+=+cross%282%29n%2F%28cross%282%29%29+%2A+%28a%2Bl%29+ ALIGN=MIDDLE  ALT=\"+2S+=+cross%282%29n%2F%28cross%282%29%29+%2A+%28a%2Bl%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "——<BR>\n" );
document.write( "7/5/17 - I corrected my last two steps, which had an error.  Apologies for that.<BR>\n" );
document.write( "7/8/17 - Meant to add that the domain restriction <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a%2Bl+%3C%3E+0+ ALIGN=MIDDLE  ALT=\"+a%2Bl+%3C%3E+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" > must accompany the answer. </SPAN>\n" );
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