If (1-x)y=y, which of the following must be true?	Choices.
A) x=-0 or y=0
B) x=-1 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=0, y=y. True   If y=0, (1-x)*0=0 True   So, x=-0= 
<gadget id="calculator">-0</gadget>
<output>0</output>
0 will be the answer.
<result>A</result>
If (1-x)y=y, which of the following must be true?