求助ＧＷＤ２７－３２，多谢！

lixiaoguangs

Q32:

If x³y⁴ = 5,000, is y = 5?

(1)     y is a positive integer.

(2)     x is an integer.

                  

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.

怎么做呢？多谢各位

Persephoner

C阿，必须x，y均为整数吧

BCorBentley

C阿，必须x，y均为整数吧

lixiaoguangs

依然不明白。我的理解是，只要知道第一个条件中y为正整数就可以判断是5了？（因为5000=(正负5)4x23)所以选A?

谢谢！

quanquanwins

C。我用倒推法。

5000=2^3x5^4，因此y是否=5取决于x和y是否同时是整数。

1）x未知的情况下y可以是5也可以是其它数。

2）x是整数时y可以是5也可以是其它数。