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truonguycb


Thực hiện phép nhân:
(a+b+c)(a^2+b^2+c^2-ab-bc-ca)=****************************???????
b,(a+b+c+d)(a^2+b^2+c^2+d^2-ab-ac-ad-bc-bd-cd)=****************************????









(a+b+c)(a^2+b^2+c^2-ab-bc-ca)=****************************???????
b,(a+b+c+d)(a^2+b^2+c^2+d^2-ab-ac-ad-bc-bd-cd)=****************************????