1) 2х - 3 = 7

2х = 7 + 3

2х = 10

х = 10/2

х = 5

2) 2(х + 3) + 5(х - 1) = 15

2х + 6 + 5х - 5 = 15

2х + 5х = 15 - 6 + 5

7х = 14

х = 14/7

х = 2

3) 5х - 10 = 15

5х = 15 + 10

5х = 25

х = 25/5

х = 5

4) 3(х - 7) + 6(х - 2) = 57

3х - 21 + 6х - 12 = 57

3х + 6х = 57 + 21 + 12

9х = 90

х = 90/9

х = 10

5) 4(7 - х) + 8(3 + х) = 64

28 - 4х + 24 + 8х = 64

8х - 4х = 64 - 28 - 24

4х = 12

х = 12/4

х = 3