Phân tích thành nhân tử a(a+2b)^3 -b(2a+b)^3
Giải thích
a(a+2b)3-b(2a+b)3=aa+b+b3−ba+a+b3
=aa+b3+3ba+b2+3b2a+b+b3−ba3+3a2a+b+3aa+b2+a+b3
=aa+b3+3aba+b2+3ab2a+b+ab3−ba3−3ba2a+b−3aba+b2−ba+b3
=a−ba+b3+3aba+bb−a+abb−ab+a
=a−ba+ba+b2−3ab−ab
=a−ba+ba2−2ab+b2
=a−ba+ba−b2
=a+ba−b3