GMAT Data Sufficiency (DS) | Re: Is xy + z = z, is |x-y| > 0 ?

In case of 1)
, y = 0 thus the answer is always yes.
Therefore it is sufficient.


In case of 2),
x = 2 and y = 0
thus the answer is yes,
but if x = 0 and y = 0
the answer is no.

Therefore it is not sufficient.
The answer is A

---