请问GWD-2-22

poorleafs

If x is negative, is x < -3?

(1) x² > 9

(2) x³ < -9

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

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

答案是A

可是条件B为什么不能推出结果呢? 想不通,请大家点化

多谢了

smilinglan

由（1）推出 x<-3 或者 x>3，由于题目说 x是负数，所以 x < -3，（1）充分。

由 (2) 推出 x < - 3 ^2/3，由于 -3 ^2/3 > -3，所以不能推出 x < -3，所以（2）不充分。

所以选A！！

poorleafs

thanks  a  lot  !!!!