If x is a positive number and a=√x∗x−x, which of the following must be true?
I. a is even
II. a is positive
III. a is an integer  Choices
A) I only  B) II only  C) III only  D) I and II  E) None of the above
If x=14 then a=√x∗x−x=1/2∗1/4−1/4=−1/8. Now, −1/8 is not an integer at all (hence not even) and also not positive, so none of the options MUST be true.   Answer: None of the above.
<result>E</result>
If x is a positive number and a=√x∗x−x, which of the following must be true?
I. a is even
II. a is positive
III. a is an integer