1) m² - 2mn + n² m - n (m-n)^2 (m+n)*(m^2-mn+n^2)
--------------------- : ---------- = ------------------- * ----------------------------- = (m-n)*(m+n) =m^2-n^2
m² - mn + n² .m³ + n3 m^2-mn+n^2 m-n
2) a² + b² - ab a³ + b³ a^2-ab+b^2 (x-y)^2 x-y
---------------------- : ------------------ = ------------------- * ---------------------------- = ----------------
x² - y² x² + y² - 2xy (x-y)*(x+y) (a+b)*(a^2-ab+b^2) (a+b)*(x+y)