Преобразуйте в дробь выражение: 1/a^2-ac-ab+bc + 2/b^2-ab-bc+ac + 1/c^2-ac-bc+ab

1 / (a²-ac-ab+bc) + 2 / (b²-ab-bc+ac) + 1 / (c²-ac-bc+ab) = 1 / (a (a-c) + b (c-a)) + 2 / (b (b-a) + c (a-b)) + 1 / (c (c-a) + b (a-c)) = 1 / (a-b) (a-c) + 2 / (a-b) (c-b) + 1 / (a-c) (b-c) = 1 / (a-b) (a-c) + 2 / (a-b) (c-b) - 1 / (a-c) (c-b) = ((c-b) + 2 (a-c) - (a-b)) / (a-b) (a-c) (c-b) = (c-b + 2a - 2c - a + b) / (a-b) (a-c) (c-b) = (a-c) / (a-b) (a-c) (c-b) = 1 / (a-b) (c-b)