Question 181708
The question is:
The number of quadruplet births Q in the United States from 1989 to 1998 can be modeled by {{{Q= -0.5t^3+11.7t^2-21.5t+218.6}}}, where t represents the number of years since 1989. For what values of t does this model no longer give realistic data? Explain your reasoning.

 Please help me and explain how you got it, so I don't just copy, but I will also understand how to solve it.
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Q(t) = -0.5t^3+11.7t^2-21.5t+218.6
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I graphed the function and found that Q(t) is negative
for x > 22.351.  And, of course Q(t) is not meaningful
for t < 0 
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{{{graph(400,300,-5,100,-300,850,-0.5x^3+11.7x^2-21.5x+218.6)}}}
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Cheers,
Stan H.