Question 61942
s(x)=-16x^2+200x+4. when should the fireworks explode so that they go off at the greatest height? What is that height?
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You have a quadratic with a=-16 and b=200
The maximum point occurs at x=-b/2a=-200/(-32)=6.25 seconds
The height at that time is 
s(6.25)=629 ft.
Cheers,
Stan H.