Question 248067: using the quadratic formula, what is the length and width of a rectangle if the length is 3 inches longer than twice the width and the area of the rectangle is 5 in^2?
Answer by oberobic(2304)   (Show Source):
You can put this solution on YOUR website! L = 2W + 3 (length = twice the width + 3)
A = L * W = 5 square inches
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Substituting what we know.
A = (2W +3) * W = 5
2W^2 + 3W = 5
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Subtract 5 from both sides
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2W^2 + 3W - 5 = 0
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We do not need to use the quadratic to solve this because it can be factored.
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(2W + 5)(W - 1) = 0
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So we have two candidate values for W: W = 1 and W = -5/2.
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Since it is not possible to have a negative value for the width, W =1 is the candidate answer.
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L = 2W + 3
L = 2(1) + 3
L = 5
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Our candidate answer is:
L = 5
W = 1
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Checking the work.
Is L*W = 5? yes.
So, we accept that answer.
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