将式a^3-5a^2b+3ab^2-3b^3-3ab^2+5ab^2-2a^3化为a^3-5a^2b+5ab^2-3b^3-2a^3=(a^3-3a^2b+3ab^2-b^3)-2a^3+2a^2b+2ab^2-2b^3-4a^2b=(a-b)^3-2(a-b)a^2+2(a-b)b^2-4a^2b=(a-b)^3-2(a+b)(a^2-b^2)-4a^2b=(a-b)^3-2(a+b)(...