Find the product:

By horizontal method:

$\left(x^{2}-y^{2}\right) \times(x+2 y)$

$=x^{2}(x+2 y)-y^{2}(x+2 y)$

$=x^{3}+2 x^{2} y-x y^{2}-2 y^{3}$

i. $e\left(x^{3}-2 y^{3}\right)+x y(2 x-y)$