SOLUTION: the concentration in part per million, of a particular drug in a patient blood x hours after the drug is administered is given by the fucntion f(x)= -x^4+11x^3-24x^2+54x. how many

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Question 321655: the concentration in part per million, of a particular drug in a patient blood x hours after the drug is administered is given by the fucntion f(x)= -x^4+11x^3-24x^2+54x. how many hours will it take the drug to be eliminated from the blood stream
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
f(x)= -x^4+11x^3-24x^2+54x. how many hours will it take the drug to be eliminated from the blood stream
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Solve -x^4+11x^3-24x^2+54x = 0 for "x":
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Factor out "-x" to get:
-x(x^3 - 11x^2 + 24x - 54) = 0
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Solve x^3-11x^2 + 24x -54 = 0
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I graphed it and found a zero at x = 9
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9)....1....-11....24....-54
.......1......-2....6....|..0
Quotient: x^2-2x+6 has complex zeroes.
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x = 9 is the only decent answer.
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Cheers,
Stan H.