document.write( "Question 238378: Hi,
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document.write( "Can you please help me with this problem?
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document.write( "Find the dimensions of a rectangle whose perimeter is 46m and whose area is 126m.
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document.write( " Also
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document.write( "The length of a rectangle is 8 cm greater then its width. Find the dimensions if its area is 105 cm
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document.write( "We need to solve it using quadratics and possibly using factoring! \n" );
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Algebra.Com's Answer #175339 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! Find the dimensions of a rectangle whose perimeter is 46m and whose area is 126m. \n" ); document.write( ": \n" ); document.write( "The perimeter equation: \n" ); document.write( "2L + 2W = 126 \n" ); document.write( "Simplify divide by 2 \n" ); document.write( "L + W = 23 \n" ); document.write( "W = (23-L); use for substitution \n" ); document.write( ": \n" ); document.write( "The area \n" ); document.write( "L * W = 126 \n" ); document.write( "Substitute (23-L) for W \n" ); document.write( "L*(23-L) = 126 \n" ); document.write( "23L - L^2 = 126 \n" ); document.write( "Arrange as a quadratic equation \n" ); document.write( "-L^2 + 23L - 126 = 0 \n" ); document.write( "Multiply by -1, easier to factor: \n" ); document.write( "L^2 - 23L + 126 = 0 \n" ); document.write( "Factors to \n" ); document.write( "(L-9)(L-14) = 0 \n" ); document.write( "Two solutions \n" ); document.write( "L = 9, then W = 14 \n" ); document.write( "or \n" ); document.write( "L = 14. then W = 9 \n" ); document.write( ": \n" ); document.write( "Check: 2(14)+2(9) = 46 \n" ); document.write( "and area: 14 * 9 = 126 \n" ); document.write( ": \n" ); document.write( "; \n" ); document.write( "The length of a rectangle is 8 cm greater then its width. Find the dimensions if its area is 105 cm \n" ); document.write( ": \n" ); document.write( "Let x = the width \n" ); document.write( "then \n" ); document.write( "(x+8) = the length \n" ); document.write( ": \n" ); document.write( "Area \n" ); document.write( "x(x+8) = 105 \n" ); document.write( "x^2 + 8x - 105 = 0; our old friend, the quadratic equation! \n" ); document.write( "factors to \n" ); document.write( "(x+15)(x-7) = 0 \n" ); document.write( "The positive solution is what we want here \n" ); document.write( "x = 7 cm, the width \n" ); document.write( "then \n" ); document.write( "7 + 8 = 15 cm; the length \n" ); document.write( "; \n" ); document.write( "It this true?: 7 * 15 = 105 sq cm \n" ); document.write( " \n" ); document.write( " |