Is xy > 0 ?
(1) x - y > -2
(2) x - 2y < -6
Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient.
由题得,2x-2y>-4, 2y-x>6.相加得X>2
同理消去X,得y>4.所以XY>0
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