document.write( "Question 556282: If I use 36 feet of fence and the square footage is 72 square feet what are the lenghts of each side of fence? Thank you \n" ); document.write( "
Algebra.Com's Answer #362099 by nerdybill(7384)\"\" \"About 
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If I use 36 feet of fence and the square footage is 72 square feet what are the lenghts of each side of fence?
\n" ); document.write( "Let x = width
\n" ); document.write( "and y = length
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\n" ); document.write( "then
\n" ); document.write( "perimeter = 2(width+length)
\n" ); document.write( "36 = 2(x+y)
\n" ); document.write( "18 = x+y (equation 1)
\n" ); document.write( ".
\n" ); document.write( "area = width*length
\n" ); document.write( "72 = xy (equation 2)
\n" ); document.write( ".
\n" ); document.write( "Solve equation 1 for y:
\n" ); document.write( "18 = x+y
\n" ); document.write( "18-x = y
\n" ); document.write( "Substitute above into equation 2 and solve for x:
\n" ); document.write( "72 = xy
\n" ); document.write( "72 = x(18-x)
\n" ); document.write( "72 = 18x-x^2
\n" ); document.write( "x^2+72 = 18x
\n" ); document.write( "x^2-18x+72 = 0
\n" ); document.write( "(x-6)(x-12) = 0
\n" ); document.write( "x = {6, 12}
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\n" ); document.write( "Solution:
\n" ); document.write( "6 feet by 12 feet\r
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