Answer:
3(x-2)+x=4x+6
Explanation:
The first equation is the one that doesn't have solution. Let's demonstrate this:

As you can observe, the equation doesn't have any solutions, because it result in a false statement.
If we solve the other equations, we would have:



The last equation has infinite solutions.
Therefore, the only one that doesn't have any solutions is
3(x-2)+x=4x+6