Its very simple - follow the BODMAS RULE.

7(x-2) - 4x = 10

7x - 14 - 4x = 10

7x-4x = 10 + 14

3x = 24

therefore x = 24/3 = 8

hence x = 8.

7(x-2) - 4x = 10

7x - 14 - 4x = 10

7x-4x = 10 + 14

3x = 24

therefore x = 24/3 = 8

hence x = 8.