A linear function f (x, y) = ax + by + c has no critical points. Therefore, the global minimum and maximum values of f (x, 3;) on a closed and bounded domain must occur on the boundary of the domain. Furthermore, it can be easily seen that if the domain is a polygon, as in the gure. then the global minimum and maximum values of 3" must occur at a vertex of the polygon. Find the global minimum and maximum values of f (x, y) on the specied polygon. f[x.y)=l5y4x+l (Give your answers as a whole numbers.)