A pet store plans to start selling mutant fish. They will have two types available: one-eyed and three-eyed fish. Denote the population of one-eyed fish by x(t), and the population of three-eyed fish by y(t). After placing the two fish species in the same tank, they realize the fish fight each other. They will however, receive additional fish every week. The store manager, who is an expert in mathematical modeling, has concluded that the weekly changes in the two populations are described by the following system: