Answer
See explanation.
Work Step by Step
Step 1. Given the condition that $x\gt y$, we have $x-y\gt 0$ or $y-x\lt0$
Step 2. Examine the given process. We can find that the second line involves a multiplication of a negative number $(y-x)$. However, the inequality symbol remains unchanged.
Step 3. The correct procedure should be that the $\gt$ symbol is changed to $\lt$ in the second line. Then we should not end up with a contradictory statement.
