document.write( "Question 1127965: A rectangle is 8 inches and 12 inches long. If the dimensions are increased by the same amount, thereby its area is increased by 69 square inches,by what amount is the side increased? \n" ); document.write( "

Algebra.Com's Answer #744450 by ikleyn(52790) $\"\"$ $\"About$

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\n" ); document.write( "A rectangle is 8 inches $\"highlight%28wide%29\"$ and 12 inches long. If the dimensions are increased by the same amount,
\n" ); document.write( "thereby its area is increased by 69 square inches,by what amount is the side increased?
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document.write( "The condition says\r\n" );
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document.write( "(8+x)*(12+x) - 8*12 = 69.\r\n" );
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document.write( "FOIL\r\n" );
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document.write( "8*12 + 12x + 8x + x^2 - 8*12 = 69\r\n" );
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document.write( "x^2 + 20x - 69 = 0\r\n" );
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document.write( "Factor left side polynomial\r\n" );
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document.write( "(x + 23)*(x-3) = 0.\r\n" );
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document.write( "The only positive root x= 3 works.\r\n" );
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document.write( "Answer.  The sides increased by 3 inches.\r\n" );
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document.write( "Check.   (8+3)*(12+3) - 8*12 = 69.     ! Correct !\r\n" );
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