我真被这种类型的题给难住了？滔滔 GWD-11-6

Q6:

For all integers x and y, the operation D is defined by xDy = (x+2)² + (y+3)².  What is the value of integer t?

(1)     t D 2 = 74

(2)     2 D t = 80

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.

大家对此类型的题做起来，有没有好的心得？

LZ   想问什么？

这种题仔细点就好了啊

选C

我是没有思路，不好意思。能给讲讲吗？

条件1，令t=x ,2=y代入方程，得到t=5或-9

同理把条件2代人，得的t=5或-11

1+2得出t唯一解5

谢谢！