[tex](\frac{x-y}{x^2-xy}-\frac{1}{x^2-y^2}:\frac{x+y}{(y-x)^2} ) : \frac{y^2}{(x+y)^2}[/tex]
[tex](\frac{x-y}{x(x-y)} -\frac{1}{-(y^2-x^2)}\cdot \frac{(y-x)(y-x)}{x+y} ):\frac{y^2}{(x+y)^2}[/tex]
[tex](\frac{1}{x}+\frac{1}{(y-x)(y+x)}\cdot \frac{(y-x)(y-x)}{x+y}):\frac{y^2}{(x+y)^2}[/tex]
[tex](\frac{1}{x}+\frac{y-x}{(x+y)^2}):\frac{y^2}{(x+y)^2}[/tex]
[tex](\frac{(x+y)^2}{x(x+y)^2}+\frac{x(y-x)}{x(x+y)^2}):\frac{y^2}{(x+y)^2}[/tex]
[tex]\frac{(x+y)^2+x(y-x)}{x(x+y)^2}\cdot \frac{(x+y)^2}{y^2}[/tex]
[tex]\frac{(x+y)^2+x(y-x)}{x\cdot y^2}[/tex]
[tex]\frac{x^2+2xy+y^2+xy-x^2}{x\cdot y^2}[/tex]
[tex]\frac{y^2+3xy}{x\cdot y^2}[/tex]
[tex]\frac{1}{x}+\frac{3}{y}[/tex]
