合并同类项2(x^2+3y^3-xy^2)-2(x^2y+2y^3)+3(x^3-xy^2+x^2y)=2x^2+6y^3-2xy^2-2x^2y-4y^3+3x^3-3xy^2+3x^2y=3x^3+2x^2+x^2y-5xy^2+2y^3带入x=-3 y=2得3x^3+2x^2+x^2y-5xy^2+2y^3=3x(-3)^3+2x(-3)^2+(-3)^2x2-5x(-3)x2^2+2x2^3=-81+18+18+60+16=31