Помогите с решением пожалуйста №2

№2.
1)
$\frac{y^2(xy^{-1}-1)^2}{x(1+x^{-1}y)^2}* \frac{y^2(x^{-2}+y^{-2})}{x(xy^{-1}+x^{-1}y)}= \frac{y^2( \frac{x}{y} -1)^2}{x(1+ \frac{y}{x} )^2}* \frac{y^2( \frac{1}{x^2}+ \frac{1}{y^2} )}{x*( \frac{x}{y} + \frac{y}{x} )}= \\ \\ = \frac{y^2( \frac{x-y}{y} )^2}{x( \frac{x+y}{x} )^2} * \frac{y^2( \frac{x^2+y^2}{x^2y^2} )}{x( \frac{x^2+y^2}{xy} )}= \frac{y^2* \frac{(x-y)^2}{y^2} }{x* \frac{(x+y)^2}{x^2} } * \frac{ \frac{x^2+y^2}{x^2} }{ \frac{x^2+y^2}{y} }= \\ \\$
$= \frac{(x-y)^2}{ \frac{(x+y)^2}{x} } *\frac{x^2+y^2}{x^2}* \frac{y}{x^2+y^2}= \frac{x(x-y)^2}{(x+y)^2}* \frac{y}{x^2}= \frac{y(x-y)^2}{x(x+y)^2}$

2)
$\frac{1-x^{-1}y}{xy^{-1}+1}= \frac{1- \frac{y}{x} }{ \frac{x}{y} +1}= \frac{ \frac{x-y}{x} }{ \frac{x+y}{y} }= \frac{x-y}{x}* \frac{y}{x+y}= \frac{y(x-y)}{x(x+y)} }$

3)
$\frac{y(x-y)^2}{x(x+y)^2}: \frac{y(x-y)}{x(x+y)}= \frac{y(x-y)^2}{x(x+y)^2}* \frac{x(x+y)}{y(x-y)}= \frac{x-y}{x+y}$