Rút gọn biểu thức: a) (x – y)(x^2 + xy + y^2);
Giải thích
a) (x – y)(x2 + xy + y2)
= x . x2 + x . xy + x . y2 – y . x2 – y . xy – y . y2
= x3 + (x2y – x2y) + (xy2 – xy2) – y3 = x3 – y3.
a) (x – y)(x2 + xy + y2)
= x . x2 + x . xy + x . y2 – y . x2 – y . xy – y . y2
= x3 + (x2y – x2y) + (xy2 – xy2) – y3 = x3 – y3.