Пошаговое объяснение:

105 : 70 = x : 4

70 * x = 105 * 4

70x = 420

х = 420 : 70

х = 6

у : 2 = 300 : 10

10 * у = 300 * 2

10у = 600

у = 600 : 10

у = 60

3/8 : х = 0,5 : 1/6

0,5 * х = 1/6 * 3/8

5/10 * х = 3/48

1/2х = 1/16

х = 1/16 : 1/2

х = 1/16 * 2/1

х = 1/8 * 1/1

х = 1/8

(2х - 1)/3 = 1/2

2(2х - 1) = 1 * 3

4х - 2 = 3

4х = 3 + 2

4х = 5

х = 5 : 4

х = 5/4

х = 1 1/4

(3х - 5)/2 = 6/3

3(3х - 5) = 6 * 2

9х - 15 = 12

9х = 12 + 15

9х = 27

х = 27 : 9

х = 3