
On the number line shown above, the tick marks are equally spaced. Which of the following statements about the numbers x, y, and z must be true?
I. xyz < 0
II. x + z = y
III. z(y - x) > 0
A. I only
B. II only
C. III only
D. I and III only
E. I, II and III.
The OA is E.
Please, can any expert explain this PS question for me? I tried to solve it but I don't understand what's the symbol mean? I need your help. Thanks.

















