\(=\left(x+y\right)^2\left(x-y\right)+y^2\left(x-y\right)\)
\(=\left(x-y\right)\cdot\left[x^2+2xy+y^2+y^2\right]\)
\(=\left(x-y\right)\left(x^2+2xy+2y^2\right)\)
= x.(x+y)2-y.(x+y)2+y2.(x-y)
= (x+y)2.(x-y)+y2.(x-y)
= (x-y).[(x+y)2+y2)
=(x-y).(x2+2xy+y2+y2)
=(x-y).(x2+2xy+2y2)
x.(x+y)2-y.(x+y)2+y2.(x-y)
= (x+y)2.(x-y)+y2.(x-y)
= (x-y).[(x+y)2+y2)
=(x-y).(x2+2xy+y2+y2)
=(x-y).(x2+2xy+2y2)