SOLUTION: Stock Value: From June 2003 until April 2004 JetBlue airlines stock (JBLU) was approximately worth P = -4t^2 + 80t - 360 where "P" denotes the price of the stock in dollars and "t"

Algebra ->  Inequalities -> SOLUTION: Stock Value: From June 2003 until April 2004 JetBlue airlines stock (JBLU) was approximately worth P = -4t^2 + 80t - 360 where "P" denotes the price of the stock in dollars and "t"      Log On


   

Question 930975: Stock Value: From June 2003 until April 2004 JetBlue airlines stock (JBLU) was approximately worth P = -4t^2 + 80t - 360 where "P" denotes the price of the stock in dollars and "t" corrersponds to months, with t=1 corresponding to January 2003. During what months was the stock value at least $36?
Using the Quadratic Formula I get 10 +/_
- (-3.167). Is this correct? The associated chart shows between August and early December 2003. I am sorry I can't load the graph chart.Thank you for your help.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Stock Value: From June 2003 until April 2004 JetBlue airlines stock (JBLU) was approximately worth P = -4t^2 + 80t - 360 where "P" denotes the price of the stock in dollars and "t" corrersponds to months, with t=1 corresponding to January 2003. During what months was the stock value at least $36?
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Solve::
-4t^2 + 80t - 360 >= 36
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-4x^2 + 80x - 396 >= 0
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Divde thru by -4 to get:
x^2 - 20x + 99 <= 0
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(x-11)(x-9) <= 0
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Ans: 9 <= x <= 11
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Cheers,
Stan H.
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