\(=\left[\dfrac{\left(x-y\right)\left(x+y\right)}{xy}-\dfrac{1}{x+y}\cdot\dfrac{x^3-y^3}{x-y}\right]\cdot\dfrac{x}{x-y}\)
\(=\left(\dfrac{x^2-y^2}{xy}-\dfrac{x^2+y^2+xy}{x+y}\right)\cdot\dfrac{x}{x-y}\)
\(=\dfrac{x^3+x^2y-xy^2-y^3-x^3y-xy^3-x^2y^2}{\left(x+y\right)\cdot xy}\cdot\dfrac{x}{x-y}\)
\(=\dfrac{x^3+x^2y-xy^2-y^3-x^3y-xy^3-x^2y^2}{y\left(x+y\right)\left(x-y\right)}\)