A ball is thrown from a height of 20 meters with an initial downward velocity of 5 m/s. The ball's height h (in meters) after t seconds is given by the following.
h=20-5t-5t²
How long after the ball is thrown does it hit the ground?
Round your answer(s) to the nearest hundredth.
(If there is more than one answer, use the "or" button.)