SOLUTION: The length of a rectangular lot is three times its width, if the length is increased by 5 meters and the width is decreased by 2 meters the original area of the lot will decrease b

Algebra ->  Rectangles -> SOLUTION: The length of a rectangular lot is three times its width, if the length is increased by 5 meters and the width is decreased by 2 meters the original area of the lot will decrease b      Log On


   

Question 1112755: The length of a rectangular lot is three times its width, if the length is increased by 5 meters and the width is decreased by 2 meters the original area of the lot will decrease by 21 square meter. Find the dimension of the lot.
Answer by josgarithmetic(39617) About Me  (Show Source):
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The length of a rectangular lot is three times its width, if the length is increased by 5 meters and the width is decreased by 2 meters the cross%28original%29 NEW area of the lot will decrease by 21 square meter. Find the dimension of the lot.
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Original dimensions:
3w and w

New dimensions:
3w+5 and w-2

New lot area decreased by 21 square meters.
3w%2Aw-%283w%2B5%29%28w-2%29=21
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3w%5E2-%283w%5E2-w-10%29=21
3w%5E2-3w%5E2%2Bw%2B10=21
w%2B10=21
highlight_green%28w=11%29------width of the original lot.
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highlight_green%2833%29------------length of the original lot.