Ответ:

1.6

Пошаговое объяснение:

8.4:(2 1/3 + 2/3) - (5/7 + 2/7)*2.6 = 8.4/(4/3+2/3) - (7/7)*2.6 = 8.4/(6/3) - 2.6 = 8.4/2 - 2.6 = 4.2 - 2.6 = 1.6