Пошаговое объяснение:

5х/6 = 40/48

5х/6 = 5/8

5х * 8 = 6 * 5

40х = 30

х = 30 : 40

х = 0,75

4/3х - 11 = 2 2/63 - 1 29/63

4/3х - 11 = 1 65/63 - 1 29/63

4/3х - 11 = 36/63

4/3х - 11 = 4/7

4/3х = 4/7 + 11

4/3х = 11 4/7

4/3х = 81/7

х = 81/7 : 4/3

х = 81/7 * 3/4

х = 243/28

х = 8 19/28