document.write( "Question 179283: Arectangle 6 feet by 8 feet has a border of uniform width around the inside of all four edges. If the border has an area of 33 square feet, how wide is the border? \n" ); document.write( "

Algebra.Com's Answer #134254 by checkley75(3666) $\"\"$ $\"About$

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6*8=48 is the area of the rectangle.
\n" ); document.write( "(6+2x)(8+2x)=48+33
\n" ); document.write( "48+16x+12x+4x^2=81
\n" ); document.write( "4x^2+28x+48-81=0
\n" ); document.write( "4x^2+28x-33=0
\n" ); document.write( "Using them quadratic equation $\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"$ we get:
\n" ); document.write( "x=(-28+-sqrt[28^2-4*4*-33])/2*4
\n" ); document.write( "x=(-28+-sqrt[784+528)/8
\n" ); document.write( "x=(-28+-sqrt1312)/8
\n" ); document.write( "x=(-28+-36.22)/8
\n" ); document.write( "x=(-28+36.22)/8
\n" ); document.write( "x=(8.22)/8
\n" ); document.write( "x=1.0277
\n" ); document.write( "Proof:
\n" ); document.write( "(6+2*1.0277)(8+2*1.0277)=81
\n" ); document.write( "(6+2.055)(8+2.055)=81
\n" ); document.write( "8.055*10.055=81
\n" ); document.write( "81~81 \n" ); document.write( "

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