3. A toy rocket is launched from a 2.1 m high platfom in such a way that its height, h (in meters) after t seconds is given by the equation h = -4.9t²+ 14.0t + 2.1

How long will it take for the rocket to hit the ground? (seconds, round to the nearest hundreth)

4. A ball is thrown upward with an initial velocity of 64 ft/s from a height of 720 ft. h = -16t²+ 64t + 720

After how many seconds will the ball reach the ground? (i.e. for what positive value of t is h = 0?)