1) 1/x² - 1/y² = (y² - x²)/(x²y²)

2) (y² - x²)/(x²y²) : (x+y)/(xy) = (y² - x²)/(x²y²) * (xy)/(x+y) = ((y-x)*(y+x)*xy)/(x²y²(x+y)) = (y-x)/(xy)

Ответ: (y-x)/(xy)