数学Prep请教

softcc

头晕了， 觉得有个prep的答案是不是错误了？我觉得应该选C 啊。

35. What is the value of xy?

(1)y = x + 1

(2) y = x2 + 1

--------------------------------------------------------------------------------------------------------------------------------------------------------【答案】E

【思路】

(1)xy=x(x+1)= file://localhost/Users/qs/Library/Caches/TemporaryItems/msoclip/0/clip_image002.gif+x--------------------------------------------------------------insufficient

(2)xy=x(file://localhost/Users/qs/Library/Caches/TemporaryItems/msoclip/0/clip_image004.gif+1)= file://localhost/Users/qs/Library/Caches/TemporaryItems/msoclip/0/clip_image006.gif+x------------------------------------------------------------insufficient

(1)(2)------------------------------------------------------------------------------------insufficient

--------------------------------------------------------------------------------------------------------------------------------------------------------

cathaynova

条件1，2结合可得以下两种情况：x=0,y=1, xy=0; x=1,y=2,xy=2. 所以答案为E。