document.write( "Question 564768: Lee has a rectangular plot to use for a flower garden. She plans to include a gravel
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document.write( "border of uniform width around the flower garden so visitors can walk completely around
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document.write( "the flowers to view them more easily. The total size of the garden and gravel border is to
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document.write( "be 15 feet by 21 feet. If Lee has enough gravel to cover 117 square feet for the border,
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document.write( "how wide will the gravel border be? What will the dimensions of the actual flower garden
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document.write( "be? Round answers to nearest tenth. \n" );
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Algebra.Com's Answer #365498 by Theo(13342)![]() ![]() You can put this solution on YOUR website! let x = the width of the border. \n" ); document.write( "the total area including the border is equal to 315 square feet. \n" ); document.write( "the area of the border is equal to 117 square feet. \n" ); document.write( "subtract 117 from 315 and you get 198 square feet for the garden. \n" ); document.write( "the length of the garden will be equal to 21 - 2x. \n" ); document.write( "the width of the garden will be equal to 15 - 2x. \n" ); document.write( "since the area of the garden is equal to the length times the width, then the equation for the area of the garden will be: \n" ); document.write( "(21 - 2x) * (15 - 2x) = 198 square feet. \n" ); document.write( "we multiply these factors out to get: \n" ); document.write( "4x^2 - 72x + 315 = 198 \n" ); document.write( "we subtract 198 from both sides of this equation to get: \n" ); document.write( "4x^2 - 72x + 117 = 0 \n" ); document.write( "this doesn't factor well so we use the quadratic formula to get: \n" ); document.write( "x = 16.19374728 or x = 1.806252715 \n" ); document.write( "x = 16.19374728 doesn't work because 21 - 2*16 is negative. \n" ); document.write( "the answer has to be x = 1.806252715 or there is no solution. \n" ); document.write( "we go back to our equation for the area of the garden. \n" ); document.write( "it is: \n" ); document.write( "(21 - 2x) * (15 - 2x) = 198 square feet. \n" ); document.write( "substituting 1.806252715 for x gets us: \n" ); document.write( "21 - 2*1.806252715) * (15 - 2*1.806252715) = 198 \n" ); document.write( "simplifying this equation gets us: \n" ); document.write( "17.38749457 * 11.38749457 = 198 \n" ); document.write( "simplifying this further gets: \n" ); document.write( "198 = 198. \n" ); document.write( "this confirms the value for x is good. \n" ); document.write( "we confirm even further by determining the area of the border. \n" ); document.write( "that will be: \n" ); document.write( "4 * x^2 plus 2 *(21 - 2x) * x plus 2 * (15-2x) * x \n" ); document.write( "substituting for x in this equation gets us 117 square feet. \n" ); document.write( "the area of the garden is 198 square feet. \n" ); document.write( "the area of the border is 117 square feet. \n" ); document.write( "the value of x = 1.806252715 feet. \n" ); document.write( "x is the width of the border. \n" ); document.write( "the length of the garden will be 21 - 2x = = 17.38749457 \n" ); document.write( "the width of the garden will be 15 - 2x = 11.38749457 \n" ); document.write( "the area of the garden is equal to (21-2x) * (15-2x) = 198 square feet. \n" ); document.write( "the equation we solved using the quadratic formula is: \n" ); document.write( "4x^2 - 72x + 117 = 0 \n" ); document.write( "in that equation: \n" ); document.write( "a = 4 \n" ); document.write( "b = -72 \n" ); document.write( "c = 117 \n" ); document.write( "the quadratic formula is: \n" ); document.write( "x = \n" ); document.write( "your answer need to be to the nearest tenth of a foot. \n" ); document.write( "that makes your answer: \n" ); document.write( "the width of the border is equal to 1.8 feet. \n" ); document.write( "the length of the garden is equal to 17.4 feet \n" ); document.write( "the width of the garden is equal to 11.4 feet.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |