7/39 - (1/13 - 2/3)= 7/39 - (1/13 3/3 - 2/3 13/13)= 7/39 - (3/39 - 26/39)= 7/39 - (-23/39)= 7/39 + 23/39= (7+23)/39= 30/39= 10/13
Ответ: 10/13.
7/39 - (1/13 - 2/3)
= 7/39 - (1/13 3/3 - 2/3 13/13)
= 7/39 - (3/39 - 26/39)
= 7/39 - (-23/39)
= 7/39 + 23/39
= (7+23)/39
= 30/39
= 10/13
Ответ: 10/13.