SOLUTION: The length of a rectangle is 6 inches less than three times its width. Find the dimensions of the rectangle if its area is 45 square inches.

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Question 196019: The length of a rectangle is 6 inches less than three times its width. Find the dimensions of the rectangle if its area is 45 square inches.
Answer by RAY100(1637) About Me  (Show Source):
You can put this solution on YOUR website!
Area = Length * Width
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BUT,,L= 3w-6,,,, given
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A=l*w = (3w-6) * w = 3w^2 -6w = 45,,,given
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3w^2 -6w -45 =0
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3 (w^2 -2w -15) +0
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Factoring
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3(w+3)(w-5) = 0
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using Zero Property
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w+3 =0,,,,w = -3,,,not realistic
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W-5 = 0, w=5,,,,ANSWER
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Checking
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w=5, L=3w-6 =3*5-6 = 15-6=9
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A = l*w = 9*5 = 45 ,,,ok