Пошаговое объяснение:

№1

1 (-5)/6 + 3 8/9 = 1/6 + 3 8/9 = 3/18 + 3 16/18 = 3 19/18 = 4 1/18

№2

3/8 * 4/5 : 2,1 = 3/8 * 4/5 : 21/10 =

3/2 * 1/5 * 10/21 = 3/10 * 10/21 = 1/1 * 1/7 = 1/7

№3

48/72 = (48 : 24)/(72 : 24) = 2/3

№4

42 : 3/7 = 42 * 7/3 = 14 * 7/1 = 98/1 = 98

№5

7/11 * 154 = 7/1 * 14 = 98/1 = 98

№6

Приведем дроби к общему знаменателю 28:

3/4 и 5/7 => (3*7)/(4*7) и (5*4)/(7*4) =>

21/28 и 20/28

21/28 > 20/28, значит: 3/4 > 5/7