SOLUTION: The length of a rectangle is 8 inches more than twice its width. Its area is 90 in-squared. find the length of the rectangle.

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Question 925999: The length of a rectangle is 8 inches more than twice its width. Its area is 90 in-squared. find the length of the rectangle.
Answer by TimothyLamb(4379)   (Show Source): You can put this solution on YOUR website!
L = 2w + 8
Lw = 90
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Lw = 90
(2w + 8)w = 90
2ww + 8w - 90 = 0
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the above quadratic equation is in standard form, with a=2, b=8 and c=-90
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to solve the quadratic equation, by using the quadratic formula, copy and paste this:
2 8 -90
into this solver: https://sooeet.com/math/quadratic-equation-solver.php
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the quadratic has two real roots at:
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w = 5
w = -9
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the negative root doesn't fit the problem statement, so use the positive root:
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w = 5
L = 2w + 8
L = 2*5 + 8
L = 18
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answer:
L = 18 inches
w = 5 inches
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