Question 818632: The length of a rectangle is 1 foot less than three times the width. The area of the rectangle is 80 square feet. Find the length and width of the rectangle. Use the quadratic equation to solve.
Answer by TimothyLamb(4379)   (Show Source):
You can put this solution on YOUR website! L = 3w - 1
Lw = 80
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Lw = 80
(3w - 1)w = 80
3ww - w - 80 = 0
3w^@ - w - 80 = 0
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the above quadratic equation is in standard form, with a=3, b=-1, and c=-80
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to solve the quadratic equation, by using the quadratic formula, plug this:
3 -1 -80
into this: https://sooeet.com/math/quadratic-equation-solver.php
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the two real roots (i.e. the two solutions), of the quadratic are:
w = 5.33333333 = 5+1/3 = 16/3
w = -5
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the negative root doesn't make sense for width, so use the positive root:
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answer:
w = 5.333 ft
L = 15 ft
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