3x - 6 = 0

3x = +6

x = 6 : 3

x = 2

----- 

x - 2 = 6 + 2

x = 6 + 2 + 2

x = 10

----- 

6x - 2 = 10

6x = 10 + 2

x = 12 : 6

x = 2

-----

8x - 2 = 10x

8x - 10x = 2

-2x = 2

x = 2 : (-2)

x = -1

-----

5x = x + 4

5x - x = 4

4x = 4

x = 4 : 4

x = 1