Um, I'm not sure what you mean by 'expected' so I may get the answer completely wrong, but this is how you would solve the inequality.
3x - 4y > 12. [x]
+ 4y
3x > 12 + 4y
÷ 3
x > (12 + 4y)/3
3x - 4y > 12. [y]
+ 4y
3x > 12 + 4y
- 12
3x - 12 > 4y
÷ 4
(3x - 12)/4 > y
