Пошаговое объяснение:

№1

1/х - 1/6 1/4х = 3/25

6 1/4 / 6 1/4х - 1/ 6 1/4х = 3/25

5 1/4 / 6 1/4х = 3/25

6 1/4х = 5 1/4 : 3/25

25/4х = 21/4 * 25/3

25/4х = 7/4 * 25/1

25/4х = 175/4

х = 175/4 : 25/4

х = 175/4 * 4/25

х = 7/1 * 1/1

х = 7/1

х = 7 (D)

№2

2/х + 1 /4 1/2х = 4/9

(4 1/2 * 2)/ 4 1/2х + 1/ 4 1/2х = 4/9

(9/2 * 2)/ 4 1/2х + 1/ 4 1/2х = 4/9

9/ 4 1/2х + 1/ 4 1/2х = 4/9

10/ 4 1/2х = 4/9

4 1/2х = 10 : 4/9

9/2х = 10 * 9/4

9/2х = 90/4

х = 90/4 : 9/2

х = 90/4 * 2/9

х = 10/2 * 1/1

х = 10/2

х = 5 (С)

№3

6/х + 1/ 1 1/2х = 2/3

(1 1/2 * 6)/ 1 1/2х + 1/ 1 1/2х = 2/3

(3/2 * 6)/ 1 1/2х + 1/ 1 1/2х = 2/3

9/ 1 1/2х + 1/ 1 1/2х = 2/3

10/ 1 1/2х = 2/3

1 1/2х = 10 : 2/3

3/2х = 10 * 3/2

3/2х = 30/2

3/2х = 15

х = 15 : 3/2

х = 15 * 2/3

х = 30/3

х = 10