Help~~~

manmuma

If x≠y,is x+y=xy?

(1)    (1-x)(1-y)=1

(2)    x^2-y^2=x^2y-xy^2  how to simplify?

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A.Statement (1) ALONE is sufficient, but statement (2) alone is notsufficient.

B.Statement (2) ALONE is sufficient, but statement (1) alone is notsufficient.

C. BOTHstatements TOGETHER are sufficient, but NEITHER statement ALONEis sufficient.

D. EACHstatement ALONE is sufficient.

E.Statements (1) and (2) TOGETHER are NOT sufficient.

Answer:

dsy1607

可以化简为(X+Y)(X-Y)=XY(X-Y),因为X不等于Y,所以直接约掉,得出x+y=xy

manmuma

dsy1607 发表于 2013-9-16 08:43
可以化简为(X+Y)(X-Y)=XY(X-Y),因为X不等于Y,所以直接约掉,得出x+y=xy

多谢啊~~~我把那个X^2Y 理解成了X的2y次方。。。。。。。。

算死我啦。。。。