Answer:
Yes to both.
Step-by-step explanation:
It is true that
In fact, if you know that x/y=1, just multiply both sides by y to get x=y. On the other hand, if you know that x=y (and they are not zero), you can divide both sides by y to get x/y=1.
Since the two expressions are equivalent, you can always use Phil's or Don's expression, at will.