Question

Tính) (x-y)^3-(x-y)(x^2+xy+y^2)

Answer 1

\(\left(x-y\right)^3-\left(x-y\right)\left(x^2+xy+y^2\right)=\left(x-y\right)^3-\left(x^3-y^3\right)\)

\(=x^3-3x^2y+3xy^2-y^3-x^3+y^3=-3x^2y+3xy^2\)

\(=-3xy\left(x+y\right)\)