document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=413587>Question 413587</A>: <I><SPAN STYLE=\"word-break: break-all;\"> designing a pool where the area 16 and the perimeter is 20. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #290203 by </B><A HREF=/tutors/aboutme.mpl?userid=nerdybill><B>nerdybill(7384)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nerdybill><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=nerdybill><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=290203\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> designing a pool where the area 16 and the perimeter is 20.<BR>\n" );
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document.write( "assuming it's a rectangular pool...<BR>\n" );
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document.write( "Let W = width<BR>\n" );
document.write( "and L = length<BR>\n" );
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document.write( "from knowledge of perimeter:<BR>\n" );
document.write( "2(W+L) = 20 <BR>\n" );
document.write( "W+L = 10 (equation 1)<BR>\n" );
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document.write( "from knowledge of area:<BR>\n" );
document.write( "WL = 16 (equation 2)<BR>\n" );
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document.write( "Solving equation 1 for L we get:<BR>\n" );
document.write( "L = 10-W<BR>\n" );
document.write( "Substitute into equation 2:<BR>\n" );
document.write( "W(10-W) = 16<BR>\n" );
document.write( "W^2+10W = 16<BR>\n" );
document.write( "W^2+10W-16 = 0<BR>\n" );
document.write( "Applying the quadratic formula we get:<BR>\n" );
document.write( "W = {1.4, -11.4}<BR>\n" );
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document.write( "Find L by substitutiting above into equation 1:<BR>\n" );
document.write( "1.4+L = 10<BR>\n" );
document.write( "L = 8.6<BR>\n" );
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document.write( "Dimensions are: 1.4 by 8.6 <BR>\n" );
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document.write( "Details of quadratic follows<BR>\n" );
document.write( "<TABLE  BORDER=1>\n" );
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document.write( " <TR><TD  ALIGN=MIDDLE>Solved by <A  rel=nofollow HREF=http://wiki.algebra.com/index.php/Tutoring_-_pluggable_solvers>pluggable</A> solver: <A  rel=nofollow HREF=quadratic.solver>SOLVE quadratic equation with variable</A></TD></TR>\n" );
document.write( "<TR><TD  ALIGN=LEFT>Quadratic equation <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=aW%5E2%2BbW%2Bc=0 ALIGN=MIDDLE  ALT=\"aW%5E2%2BbW%2Bc=0\"   DISABLED_style= \"max-width:90%; height:auto;\" > (in our case <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1W%5E2%2B10W%2B-16+=+0 ALIGN=MIDDLE  ALT=\"1W%5E2%2B10W%2B-16+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" >) has the following solutons:<BR>\n" );
document.write( "  <BR>\n" );
document.write( "  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=W%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca ALIGN=MIDDLE  ALT=\"W%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "  <BR>\n" );
document.write( "  For these solutions to exist, the <U>discriminant</U> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=b%5E2-4ac ALIGN=MIDDLE  ALT=\"b%5E2-4ac\"   DISABLED_style= \"max-width:90%; height:auto;\" > should not be a negative number.<BR>\n" );
document.write( "  <BR>\n" );
document.write( "  First, we need to compute the discriminant <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=b%5E2-4ac ALIGN=MIDDLE  ALT=\"b%5E2-4ac\"   DISABLED_style= \"max-width:90%; height:auto;\" >: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=b%5E2-4ac=%2810%29%5E2-4%2A1%2A-16=164 ALIGN=MIDDLE  ALT=\"b%5E2-4ac=%2810%29%5E2-4%2A1%2A-16=164\"   DISABLED_style= \"max-width:90%; height:auto;\" >.<BR>\n" );
document.write( "  <BR>\n" );
document.write( "  Discriminant d=164 is greater than zero. That means that there are two solutions: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+x%5B12%5D+=+%28-10%2B-sqrt%28+164+%29%29%2F2%5Ca ALIGN=MIDDLE  ALT=\"+x%5B12%5D+=+%28-10%2B-sqrt%28+164+%29%29%2F2%5Ca\"   DISABLED_style= \"max-width:90%; height:auto;\" >.<BR>\n" );
document.write( "  <BR>\n" );
document.write( "    <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=W%5B1%5D+=+%28-%2810%29%2Bsqrt%28+164+%29%29%2F2%5C1+=+1.40312423743285 ALIGN=MIDDLE  ALT=\"W%5B1%5D+=+%28-%2810%29%2Bsqrt%28+164+%29%29%2F2%5C1+=+1.40312423743285\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "    <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=W%5B2%5D+=+%28-%2810%29-sqrt%28+164+%29%29%2F2%5C1+=+-11.4031242374328 ALIGN=MIDDLE  ALT=\"W%5B2%5D+=+%28-%2810%29-sqrt%28+164+%29%29%2F2%5C1+=+-11.4031242374328\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "    <BR>\n" );
document.write( "    Quadratic expression <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1W%5E2%2B10W%2B-16 ALIGN=MIDDLE  ALT=\"1W%5E2%2B10W%2B-16\"   DISABLED_style= \"max-width:90%; height:auto;\" > can be factored:<BR>\n" );
document.write( "  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1W%5E2%2B10W%2B-16+=+1%28W-1.40312423743285%29%2A%28W--11.4031242374328%29 ALIGN=MIDDLE  ALT=\"1W%5E2%2B10W%2B-16+=+1%28W-1.40312423743285%29%2A%28W--11.4031242374328%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "  Again, the answer is: 1.40312423743285, -11.4031242374328.\n" );
document.write( "Here's your graph:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B10%2Ax%2B-16+%29 ALIGN=MIDDLE  ALT=\"graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B10%2Ax%2B-16+%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ></TD></TR>\n" );
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document.write( " </SPAN>\n" );
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