(a+b)^3=a^3+3a^2b+3ab^2+b^3(a-b)^3=a^3-3a^2b+3ab^2-b^3a^3-b^3=(a-b)(a^2+ab+b^2)a^3+b^3=(a+b)(a^2-ab+b^2)a^3+b^3+c^3-3abc=(a+b+c)(a^2+b^2+c^2-ab-bc-ca)大概就这几个
