Пошаговое объяснение:
5/9 - 1/6 + 2/3 : 5/6 - 1/2 - 2/9 =
= 5/9 - 1/6 + 2/3 * 6/5 - 1/2 - 2/9 =
= 5/9 - 1/6 + 4/5 - 1/2 - 2/9 =
= (5/9 - 2/9) - (1/6 + 1/2) + 4/5 =
= 3/9 - (1/6 + 3/6) + 4/5 =
= 3/9 - 4/6 + 4/5 =
= 1/3 - 2/3 + 4/5 =
= -1/3 + 4/5 =
= -5/15 + 12/15 = 7/15