Is x > 0 ?
(1) xy > 0
(2) x + y > 0
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.
(1)xy同号 单独NS
(2)NS
(1) + (2) x,y都是正数 因为负数加上另一个负数不可能>0
所以x是正数,> 0, sufficient