If (1*x)y=y, which of the following must be true?
Choose the correct choice.
A) x=-1 or y=0 B) x=0 or y=0 C) x=1 or y=1 D) x=-1 or y=-1 E) x=0 or y=1
We have (1*x)y=y.   If x=1, y=1 True   If y=1, (1*x)*1=1True   So, x=1 or y=1will be the answer.
<result>C</result>
If (1*x)y=y, which of the following must be true?