2.11.11 Function extreme

condition: Find the smallest and largest values ​​of the function \( z=f(x, y) \) in the closed region \( D \), defined by the system of inequalities. Make a drawing of the area \(D\). \[ z=3-2 x^{2}-x y-y^{2}, z \leq 1, y \geq 0, y \leq x \]