document.write( "Question 157114: If the sides of a square are lengthened by 5cm, the area becomes 81cm^2. Find the length of a side of the original square. \n" ); document.write( "
Algebra.Com's Answer #115990 by ankor@dixie-net.com(22740)\"\" \"About 
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If the sides of a square are lengthened by 5cm, the area becomes 81cm^2.
\n" ); document.write( " Find the length of a side of the original square.
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\n" ); document.write( "let x = side of original square
\n" ); document.write( "then
\n" ); document.write( "(x+5) = side of the new square
\n" ); document.write( "and
\n" ); document.write( "(x+5)^2 = area of the new square
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\n" ); document.write( "The problems states:
\n" ); document.write( "(x+5)^2 = 81
\n" ); document.write( "FOIL
\n" ); document.write( "x^2 + 10x + 25 = 81
\n" ); document.write( ":
\n" ); document.write( "x^2 + 10x + 25 - 81 = 0
\n" ); document.write( ":
\n" ); document.write( "x^2 + 10x - 56 = 0; a quadratic equation
\n" ); document.write( "Factors to:
\n" ); document.write( "(x+14)(x-4) = 0
\n" ); document.write( "Positive solution
\n" ); document.write( "x = +4 is the side of the original square
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\n" ); document.write( ":
\n" ); document.write( "Check solution: New square side; 4 + 5 which has an area of 81 sq/cm \n" ); document.write( "
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