1) (50 Points) Suppose the fraction of SUBARU car owners who chose another new Subaru can be modeled by the following function: S(x, y) = 0.2 x - 0.4 y + 0.8 x2 + 0.5 y2 - 0.8 xy + 0.7 where x is the fraction of Toyota car owners who remained loyal to Toyota and y is the fraction of Honda car owners remaining loyal to Honda. Locate and classify all the critical points, find that S and interpret your answer (write your values x, y, and S as %)