单选题
【正确答案】
D
【答案解析】Given that x+y=4, there are infinitely many pairs of (x, y) values that make the equation true. For example:
2+2=4
5+(-1)=4
(-3)+7=4
From the three examples above, it is clear that there are instances when x=y, x＞y, and x＜y. Thus the relationship cannot be determined from the information given.
2+2=4
5+(-1)=4
(-3)+7=4
From the three examples above, it is clear that there are instances when x=y, x＞y, and x＜y. Thus the relationship cannot be determined from the information given.