下列各式中,结果为1-2xy的平方+x的平方y的4次方A.（-1-x平方y平方）的平方B.（-1+xy平方）平方C.（-1+x的平方y的平方）平方D.（-1-xy的平方）平方

下列各式中,结果为1-2xy的平方+x的平方y的4次方A.（-1-x平方y平方）的平方B.（-1+xy平方）平方C.（-1+x的平方y的平方）平方D.（-1-xy的平方）平方
下列各式中,结果为1-2xy的平方+x的平方y的4次方
A.（-1-x平方y平方）的平方
B.（-1+xy平方）平方
C.（-1+x的平方y的平方）平方
D.（-1-xy的平方）平方

下列各式中,结果为1-2xy的平方+x的平方y的4次方A.（-1-x平方y平方）的平方B.（-1+xy平方）平方C.（-1+x的平方y的平方）平方D.（-1-xy的平方）平方
答案当然是B了,只看中间项,只有一正、一负的时候平方以后中间项才能是负的啊.另外看中间项谁有平方就OK了.

1 Do not be lonely to fall in love, time is of the devil, Over time, if you are a passionate people, if not love each other, that time will also have feelings, and finally how do you do?

2...

全部展开

1 Do not be lonely to fall in love, time is of the devil, Over time, if you are a passionate people, if not love each other, that time will also have feelings, and finally how do you do?

2. Do not go to bed with others, or will experience a true love, but he is keeping oneself clean and principled man, you will regret the actions of the year.

3. the requirements of the other party is not a virgin, think he is not a virgin, if you can, if not, how can you?

4. not because of his appearance as the other party's intention to give up the pursuit, and looks just a momentary impression, the real decision depends on whether the combination of the two sides of the character, I've seen the guy with ugly, beautiful women with ugly man too much.

5. and a different lifestyle there are many people who love it does not matter, marriage should be careful, think about whether you can long endure each other's different.

6. often heard masculine and feminine, you know what flavor of masculinity, femininity, what is the taste it? Masculinity is open-minded brave, gentle and feminine is thoughtful.

7. and smart people love very happy, because they are humorous,Oakley sunglasses, talking, but there is always a crisis, because people tend to change of heart, and honest people in love would be assured, but life is is also very boring.

8. Some people always complain about no good, one or two does not matter much have a problem. First you need to review what you have no problem themselves, if not, then you have to look at your eyes,Mac cosmetics, why every time you run into bad guys?

9. Some people say that men who change of heart,mac blush, nine head of cattle are also not pull back, do women change of heart, nine head of cattle to pull back? Only the biological differences between men and women, psychological similar.

10. If you love a person, he will be willing to change, if a person in front of you its own way, set the behavior you do not like the expense, then he is not love you. So you not care about him or he is not concerned about you, then you do not love him or he does not love you, and do not think they have been very careless, or believe he is a careless person. Met his true love, can also become a coward brave, the same token, a ghost can also become carefully careless.

11. The mature never ask the past, the wise never ask the present, open-minded people do not ask the next eleven classic famous love

收起

原式可化成：
1²-2xy²+x²（y²）²
=（1-xy²）²=（xy²-1）²=（-1+xy²）²
所以选择B