Question 1173136
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please help

A ball is thrown from an initial height of 5 feet with an initial upward velocity of 21 ft/s. 
The ball's height h (in feet) after t seconds is given by the following.

h=5+21t-16t^2

Find all values of  for which the ball's height is  feet.
Round your answer(s) to the nearest hundredth.
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