2x/(xy-y²) + 2y/(xy-x²) - (x+y)/xy
= 2x/y(x-y) + 2y/(x(y-x) - (x+y)/xy also HN xy(x-y) erweitern gibt
= 2x^2 /xy(x-y) - 2y^2/(xy(x-y) - (x+y)(x-y)/xy(x-y)
= (2x^2 - 2y^2 - (x^2 -y^2 ) ) / xy(x-y)
= (2x^2 - 2y^2 - x^2 + y^2 ) ) / xy(x-y)
= (x^2 - y^2 ) / xy(x-y)
= (x - y)(x+y) ) / xy(x-y)
= (x+y) ) / xy