Q019 :b^2*c^2*x^3*y + a^2*c^2*x^2*y^2 - b^2*c^2*x^2*y^2 - a^2*c^2*x*y^3 - b^2*c^2*x^3*z + 2*a^2*b^2*x^2*y*z - 2*b^4*x^2*y*z - 2*a^2*c^2*x^2*y*z + 2*c^4*x^2*y*z + 2*a^4*x*y^2*z - 2*a^2*b^2*x*y^2*z + 2*b^2*c^2*x*y^2*z - 2*c^4*x*y^2*z + a^2*c^2*y^3*z - a^2*b^2*x^2*z^2 + b^2*c^2*x^2*z^2 - 2*a^4*x*y*z^2 + 2*b^4*x*y*z^2 + 2*a^2*c^2*x*y*z^2 - 2*b^2*c^2*x*y*z^2 + a^2*b^2*y^2*z^2 - a^2*c^2*y^2*z^2 + a^2*b^2*x*z^3 - a^2*b^2*y*z^3 = 0