He fish population in a certain lakes rises and falls according to the formula
F=(30+17t-t^2)

F is the number of fish at time t, where t is measured in years since January 1, 1992, when the fish population was first estimated.

A). On what date will the fish population again be the same as on January 1, 1992?
B) By what date will all the fish in the lake have died?