The equation y=−16t2+28t+144 describes the height y (in feet) at time t (in seconds) of a ball tossed up in the air at 28 feet per second from a height of 144 feet from the ground. In how many seconds will the ball hit the ground?
Plugging in different values of t, you can find that t = 5.5 works.
Sorry; I just tried that and its incorrect!
0=−15t2+28t+144t=−28±√784+8640−30t=−28±√9424−30t=+28+4√58930t≈4.17sec
+660 
