By observation, we can see that these two equations are inconsistent. Note the left side of the first equation is -3y. The second equation is -6y, which is exactly 2 times the first equation. For these equations to be consistent, the right side of the second equation must be 2 times the right side of the first equation. It isn't, therefore the equations are not consistent.
2(0-2x) does not equal 3-4x