Выполните действие. (-4\5-4\7)*(5целых7\9-7целых11\12)

(-4/5 - 4/7) * (5 7/9 - 7 11/12) = 2 целых 14/15

1) -4/5 - 4/7 = -(28/35 + 20/35) = -48/35 
2) 5 7/9 - 7 11/12 = -(7 11/12 - 5 7/9) = -(7 33/36 - 5 28/36) = -2 5/36
3) -48/35 * (-2 5/36) = 48/35 * 77/36 = (8*11)/(5*6) = 88/30 = 2 28/30 = 2 14/15