(a+b+c)×(d+e+f)=ad+ae+af+bd+be+bf+cd+ce+cf(a+b)×(a-b)=a^2-b^2(a+b)×(a+b)=(a+b)^2=a^2+2ab+b^2(a+b+c)×(a+b+c)=(a+b+c)^2=a^2+b^2+c^2+2ab+2ac+2bc(a+b)×(a+b)×(a+b)=(a+b)^3=a^3+3a^2b+3ab^2+b^3多项式乘...