请教GWD 2道数学题，费解。谢谢指点！

bingbing13

What is the value of (x - y)的4次方?
(1)      The product of x and y is 7.
(2)      x and y are integers.
    
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.

(1)      y = 50
(2)      z = 40
    
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.
2. 4的3次方+4的3次方+4的3次方+4的3次方=？

Ivyyaya

貌似第一题选C，单纯知道XY乘积无法知道X-Y值，两个条件加在一起，只能X为1，Y为7或者相反，这两种情况下X-Y的四次方都等与6的四次方
第二题是4的四次方，不知道要具体值还是什么。

我文科生数学也不好，仅供参考

大荣

同意三楼，第一题选C。补充一下，条件2只说整数，有可能是负整数，那么x，y取值两种可能，1,7与-1,-7，但总归|x-y|=6，所以(x-y)^4还是唯一确定的。