Tìm kiếm
Nam
Câu 1
(a + b + c )(ab + bc + ca) - abc
= a^2b + abc + a^2c + b^2a + b^2c + abc + abc + bc^2 + c^2a - abc
= a^2b + a^2c + b^2a + b^2c + c^2b + c^2a + 2abc
= a(c^2 + ab + ca + bc) + b(c^2 + ab + ca + bc )
= (a+b)(c^2 + ab + ca + bc)
Câu 1
(a + b + c )(ab + bc + ca) - abc
= a^2b + abc + a^2c + b^2a + b^2c + abc + abc + bc^2 + c^2a - abc
= a^2b + a^2c + b^2a + b^2c + c^2b + c^2a + 2abc
= a(c^2 + ab + ca + bc) + b(c^2 + ab + ca + bc )
= (a+b)(c^2 + ab + ca + bc)
