(x/y^2-1/x):(1/y+1/x)

=(х*х/у^2*x-1*y^2/x*y^2):(18xy/y^2*x+1*y^2/x*y^2)=x^2-y^2/y^2x^xy+y^2/y^2x=x^2-y^2/xy+y^2=(x-y)(x+y)/y(x+y)=x-y/y