Для начала решим дробь 11/14 - 2 13/14:

11/14 - 2 13/14 = 11/14 - (2 + 13/14) = 11/14 - 27/14 = -16/14 = -8/7

Теперь вычислим 5 - (-8/7) + 3 12/14:

5 - (-8/7) + 3 12/14 = 5 + 8/7 + 3 + 12/14 = 35/7 + 8/7 + 42/14 = 53/7 + 6/14 = 106/14 + 6/14 = 112/14 = 8

Итак, 5-11/14-2 13/14+3 12/14 = 8.