document.write( "Question 1185330: The length of a rectangle is 4cm less than thrice its width. If the area is 160 sq cm , what are the dimensions of the rectangle?
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Algebra.Com's Answer #816144 by ikleyn(52790) $\"\"$ $\"About$

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\n" ); document.write( "The length of a rectangle is 4cm less than thrice its width.
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document.write( "Let w be the width, in centimeters;\r\n" );
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document.write( "then the length is 3w-4 centimeters.\r\n" );
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document.write( "The area equation is\r\n" );
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document.write( "    w*(3w-4) = 160.\r\n" );
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document.write( "Reduce it to the standard form quadratic equation\r\n" );
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document.write( "    3w^2 - 4w - 160 = 0\r\n" );
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document.write( "To solve it, use the quadratic formula\r\n" );
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document.write( "    w =  = .\r\n" );
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document.write( "You need only positive root  \r\n" );
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document.write( "    w =  =  = 8.\r\n" );
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document.write( "ANSWER.  The width is 8 cm;  the length is  3*8-4 = 20 cm.\r\n" );
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document.write( "CHECK.  We check the area :   6*20 = 160 cm^2.    ! Correct !\r\n" );
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