Auniversal set contains only sets a and b. if a∩b = ø and a and b are not the empty set, then all of the following are true except

a and b are disjoint.
a is equal to b complement.
a∪b={}
a is not a subset of b.

The height of a flare fired from the deck of a ship in distress can be modeled by h(t)= -2(8t^2-52t-28), where h is the height of the flare above water and t is the time in seconds. a. find the time it takes the flare to hit the water.