document.write( "Question 861680: A rectangle is drawn so that the width is 4 feet shorter than the length. The area of the rectangle is 12 square feet. Find the length of the rectangle. \n" ); document.write( "

Algebra.Com's Answer #519166 by ben720(159) $\"\"$ $\"About$

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$\"A=12\"$
\n" ); document.write( " $\"lw=12\"$
\n" ); document.write( "Because the width is 4 ft shorter,
\n" ); document.write( " $\"l%28l-4%29=12\"$
\n" ); document.write( "Distribute the l
\n" ); document.write( " $\"l%5E2-4l=12\"$
\n" ); document.write( "Subtract 12 from both sides
\n" ); document.write( " $\"l%5E2-4l-12=0\"$
\n" ); document.write( "Use the quadratic formula
\n" ); document.write( " $\"l+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"$
\n" ); document.write( " $\"l+=+%284+%2B-+sqrt%28+-4%5E2-4%2A1%2A-12+%29%29%2F%282%2A1%29+\"$
\n" ); document.write( " $\"l+=+%284+%2B-+sqrt%2816%2B48%29%29%2F%282%29+\"$
\n" ); document.write( " $\"l=%284%2B-sqrt%2864%29%29%2F2\"$
\n" ); document.write( " $\"l=%284%2B8%29%2F2\"$ OR $\"l=%284-8%29%2F2\"$
\n" ); document.write( " $\"l=12%2F2\"$ OR $\"l=-4%2F2\"$
\n" ); document.write( " $\"l=6\"$ OR $\"l=-2\"$
\n" ); document.write( "Because the length can't be negative, l=6. Because the width is 4 less, it's 2.
\n" ); document.write( "

The length is 6 feet

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