Tìm min B

Tìm min B = 2x^2 + y^2 - 2x + 2y + 2xy + 2
F = x^4 -8xy - x^3y +x2y2 - xy^3 + y^4 + 200
Tìm max : B = -x^2 - 4y^2 + 2x + 10y + 2xy +5
E = -y^2 - 11x^2 - 6xy + 5x - 7