6x^2-7xy-3y^2-xz+7yz-2z^22x^4-x^3-6x^2-x+2(x+1)^4+(x+3)^4-272xy(xy+1)+(xy+3)-2(x+y+0.85)-(x+y-1)^2x^3+8y^3-z^3+6xyzx^2+5xy+6y^2+8x+18y+12x^2+2xy-8y^2+2x+14y-33a3b2c－6a2b2c2＋9ab2c3xy＋6－2x－3yx2(x－...