Решите выражение (4/5+4/7) * (7 целых11/12-5 целых7/9)

(4/5+4/7) * (7 11/12 - 5 7/9) =

= ((4 * 7) / (5 * 7) + (4 * 5) / (7 * 5)) * ((7 * 12 + 11) / 12 - (5 * 9 + 7) / 9) =

= (28/35 + 20/35) * ((84 + 11) / 12 - (45 + 7) / 9) =

= 48/35 * (95/12 - 52/9) =

= 48/35 * ((95*3) / (12*3) - (52*4) / (9*4)) =

= 48/35 * (285/36 - 208/36) =

= 48/35 * 77/36 =

= (48 * 77) / (35 * 36) = (4 * 11) / (5 * 3) = 44/15 = 2 14/15.

Ответ: 2 целых 14/15.