Answer:
<h2>3(x-2)+x=4x+6</h2>
Step-by-step explanation:
The first equation is the one that doesn't have solution. Let's demonstrate this:

<em>As you can observe, the equation doesn't have any solutions, because it result in a false statement.</em>
<em></em>
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
<h3>3(x-2)+x=4x+6</h3>