6 (7 2/9 + 5 1/6)
= 6 (63/9 + 31/6)
= 6 (7 + 9/6)
= 6 (7 + 3/2)
= 6 (14/2 + 3/2)
= 6 (17/2)
= 6*17 / 2
= 102 / 2
= 51

Ответ: 51