Пошаговое объяснение:

1)

2/5 /(3/5х - 1/5) - 1/5 = 1/20

2/5 /(3/5х - 1/5) = 1/20 + 1/5

2/5 /(3/5х - 1/5) = 1/20 + 4/20

2/5 /(3/5х - 1/5) = 5/20

2/5 /(3/5х - 1/5) = 1/4

3/5х - 1/5 = 2/5 : 1/4

3/5х - 1/5 = 2/5 * 4/1

3/5х - 1/5 = 8/5

3/5х = 8/5 + 1/5

3/5х = 9/5

х = 9/5 : 3/5

х = 9/5 * 5/3

х = 3/1 * 1/1

х = 3/1

х = 3

2)

2/3 /(5/6х - 1/6) + 1/3 = 7/9

2/3 /(5/6х - 1/6) = 7/9 - 1/3

2/3 /(5/6х - 1/6) = 7/9 - 3/9

2/3 /(5/6х - 1/6) = 4/9

5/6х - 1/6 = 2/3 : 4/9

5/6х - 1/6 = 2/3 * 9/4

5/6х - 1/6 = 1/1 * 3/2

5/6х - 1/6 = 3/2

5/6х = 3/2 + 1/6

5/6х = 9/6 + 1/6

5/6х = 10/6

х = 10/6 : 5/6

х = 10/6 * 6/5

х = 2/1 * 1/1

х = 2/1

х = 2

3)

3/4 /(1/8х + 3/8) - 1/2 = 5/14

3/4 /(1/8х + 3/8) = 5/14 + 1/2

3/4 /(1/8х + 3/8) = 5/14 + 7/14

3/4 /(1/8х + 3/8) = 12/14

1/8х + 3/8 = 3/4 : 12/14

1/8х + 3/8 = 3/4 * 14/12

1/8х + 3/8 = 1/2 * 7/4

1/8х + 3/8 = 7/8

1/8х = 7/8 - 3/8

1/8х = 4/8

х = 4/8 : 1/8

х = 4/8 * 8/1

х = 4/1 * 1/1

х = 4/1

х = 4