document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=579237>Question 579237</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A lawn is 90 feet long and 40 feet wide. By cutting along the perimeter, how wide is this border if 1/3 of the grass is cut?\r<BR>\n" );
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document.write( "More info: provided solution is 5 feet.  Student says answer must be derived by using quadratic formula.\r<BR>\n" );
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document.write( "X=width of the border<BR>\n" );
document.write( "2(90)(x)+2(40)(x)=(90 times 40)/3\r<BR>\n" );
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document.write( "Which then does not result in a constant for a to be used in the quadratic formula.  B is 260 and c is negative 1200.  Since the constant a is zero, i get a divide by zero using the quadratic formula which means to me the answer is infinite but the provided answer is 5.  I have made an error but i can't find it.  Please advise. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #370911 by </B><A HREF=/tutors/aboutme.mpl?userid=josmiceli><B>josmiceli(19441)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josmiceli><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=josmiceli><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=370911\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The area of the grass is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+90%2A40+=+3600+ ALIGN=MIDDLE  ALT=\"+90%2A40+=+3600+\"   DISABLED_style= \"max-width:90%; height:auto;\" > ft2<BR>\n" );
document.write( "1/3 of the area is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+1200+ ALIGN=MIDDLE  ALT=\"+1200+\"   DISABLED_style= \"max-width:90%; height:auto;\" > ft2<BR>\n" );
document.write( "If the border is of uniform width, and this width<BR>\n" );
document.write( "is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+x+ ALIGN=MIDDLE  ALT=\"+x+\"   DISABLED_style= \"max-width:90%; height:auto;\" >, then the total area minus the border is<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%2840+-+2x%29%2A%2890+-+2x%29+=+3600+-+1200+ ALIGN=MIDDLE  ALT=\"+%2840+-+2x%29%2A%2890+-+2x%29+=+3600+-+1200+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+3600+-+180x+-+80x+%2B+4x%5E2+=+2400+ ALIGN=MIDDLE  ALT=\"+3600+-+180x+-+80x+%2B+4x%5E2+=+2400+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+4x%5E2+-+260x+%2B+1200+=+0+ ALIGN=MIDDLE  ALT=\"+4x%5E2+-+260x+%2B+1200+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+x%5E2+-+65x+%2B+300+=+0+ ALIGN=MIDDLE  ALT=\"+x%5E2+-+65x+%2B+300+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Using quadratic formula:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ ALIGN=MIDDLE  ALT=\"+x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+=+1+ ALIGN=MIDDLE  ALT=\"+a+=+1+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+=+-65+ ALIGN=MIDDLE  ALT=\"+b+=+-65+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+300+ ALIGN=MIDDLE  ALT=\"+c+=+300+\"   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-%28-65%29+%2B-+sqrt%28+%28-65%29%5E2+-+4%2A1%2A300+%29+%29+%2F+%282%2A1%29+ ALIGN=MIDDLE  ALT=\"+x+=+%28-%28-65%29+%2B-+sqrt%28+%28-65%29%5E2+-+4%2A1%2A300+%29+%29+%2F+%282%2A1%29+\"   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+65+%2B-+sqrt%28++4225+-4%2A1%2A300+%29%29%2F%282%2A1%29+ ALIGN=MIDDLE  ALT=\"+x+=+%28+65+%2B-+sqrt%28++4225+-4%2A1%2A300+%29%29%2F%282%2A1%29+\"   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+65+%2B-+sqrt%28++4225+-+1200+%29+%29+%2F+2+ ALIGN=MIDDLE  ALT=\"+x+=+%28+65+%2B-+sqrt%28++4225+-+1200+%29+%29+%2F+2+\"   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+65+%2B-+sqrt%28+3025+%29+%29+%2F+2+ ALIGN=MIDDLE  ALT=\"+x+=+%28+65+%2B-+sqrt%28+3025+%29+%29+%2F+2+\"   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+65+%2B-+55+%29+%2F+2+ ALIGN=MIDDLE  ALT=\"+x+=+%28+65+%2B-+55+%29+%2F+2+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+x+=+10%2F2+ ALIGN=MIDDLE  ALT=\"+x+=+10%2F2+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+x+=+5+ ALIGN=MIDDLE  ALT=\"+x+=+5+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "and, with negative square root,<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+x+=+120%2F2+ ALIGN=MIDDLE  ALT=\"+x+=+120%2F2+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+x+=+60+ ALIGN=MIDDLE  ALT=\"+x+=+60+\"   DISABLED_style= \"max-width:90%; height:auto;\" > ( not possible )<BR>\n" );
document.write( "The border is 5 ft wide<BR>\n" );
document.write( "check:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%2840+-+2x%29%2A%2890+-+2x%29+=+3600+-+1200+ ALIGN=MIDDLE  ALT=\"+%2840+-+2x%29%2A%2890+-+2x%29+=+3600+-+1200+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%2840+-+2%2A5%29%2A%2890+-+2%2A5%29+=+3600+-+1200+ ALIGN=MIDDLE  ALT=\"+%2840+-+2%2A5%29%2A%2890+-+2%2A5%29+=+3600+-+1200+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%28+40+-+10+%29%2A%28+90+-+10+%29+=+3600+-+1200+ ALIGN=MIDDLE  ALT=\"+%28+40+-+10+%29%2A%28+90+-+10+%29+=+3600+-+1200+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+30%2A80+=+2400+ ALIGN=MIDDLE  ALT=\"+30%2A80+=+2400+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+2400+=+2400+ ALIGN=MIDDLE  ALT=\"+2400+=+2400+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "OK </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );