Answer:
<h2>Totally disagree with Lin.</h2>
When an equation don't have solution, it's because variables are cancelled or eliminated.
In this case, if we operate left side, we will have a term 14x, and the right side of the equation there's also 14x, that means that variable will be eliminated, like this:

As you can see, the equation ends in a false result, that means it doesn't have any solution, and we can tell by just seeing the first line of the equation like Lin says.
So, totally disagree with Lin, she can tell from the beginning that the equation doesn't have a solution.