Okay so I have this problem and am not sure where to start. Can anyone help?:

An arrow shot verticaly into the air from ground level with a cross bow reaches a maximum height of 484 feet after 5.5 seconds of flight. Let the quadratic function d(t) represent the distance above ground in feet t seconds after the arrow is released.

(a)Find d(t) and state its domain.

(b)At what times (to two decimal places) will the arrow be 250 ft. above the ground?