Problem Solving (PS) | Re: If x and y are integers such that x > y, which of the following CANNOT

When X>Y,
These are the possible cases

X Y
+ -
+ 0
+ +
- -

The question is asking CANNOT be positive, we will prove CAN be positive and eliminate that answer.

I. y(y – x)
If both are negative the result will be positive, hence eliminate answer choices a and d.
II. y(x – y)
If both are positive the result will be positive, hence eliminate answer choice b and e.
III. (x - y)/(y - x)

Answer is C, which is the only choice left.

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