Question 536949: The length of a rectangle is 2 less than 3 times it's width. The perimeter of the rectangle is 36 in. Find the length and the width.
Answer by lmeeks54(111)   (Show Source):
You can put this solution on YOUR website! Let L = the length of the long sides
Let W = the length of the short sides
The area, A = L * W
The perimeter, P = 2L + 2W
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L = 3W - 2
P = 2L + 2W = 36
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Substitute the equality for L into the perimeter equation and solve for W:
36 = 2(3w - 2) + 2W
36 = 6W - 4 + 2W
36 = 8W - 4
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Add 4 to both sides to simplify:
36 + 4 = 8W - 4 + 4
40 = 8W
5 = W
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Go back to the 1st equation and solve using W = 5:
L = 3(5) - 2
L = 15 - 2
L = 13
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L = 13, W = 5 is the answer
Before you're done, always check your work:
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P = 2(13) + 2(5) = 36
36 = 26 + 10
36 = 36 checks
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Solution checks, you're done.
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cheers,
Lee
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