SOLUTION: A rectangle has a width 4cm less than the length. If a new rectangle is formed by increasing the width 5cm and decreasing the length 3cm, the area of this resulting rectangle is 11

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Question 801159: A rectangle has a width 4cm less than the length. If a new rectangle is formed by increasing the width 5cm and decreasing the length 3cm, the area of this resulting rectangle is 117cm^2. What are the dimensions of the original rectangle? I'm not entirely sure how to approach this problem.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
A rectangle has a width 4cm less than the length.
Length = L
Width = L-4
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If a new rectangle is formed by increasing the width 5cm and decreasing the length 3cm, the area of this resulting rectangle is 117cm^2.
Length = L-3
Width = L-4+5 = L+1
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Equation:
Area = length * width
117 = (L-3)(L+1)
L^2 -2L -3 = 117
L^2 -2L - 120 = 0
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Factor:
(L-12)(L+10) = 0
Positive solution:
L = 12 cm (original length)
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W = L-4 = 8 cm (original width)
What are the dimensions of the original rectangle?
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Cheers,
Stan H.
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