问题 填空题

因式分解:x3yxy =         

答案

xyx-1)(x + 1)

先提公因式xy,再用平方差公式进行因式分解.

解答:解:原式=xy(x2-1)

=xy(x-1)(x+1).

问答题

某企业现计划从国外引进一套设备进行企业技术设备更新改造。该设备的离岸价格为180万美元,海上运输及保险费为20万美元,运到中国口岸后需要缴纳如下费用:①关税41.5万元;②国内运输费用12.7万元;③外贸手续费(费率为3.5%);④增值税及其他附加税费87.5万元。通过扩大生产规模,该企业年销售收入可增加到4500万元,年经营成本提高到3200万元,设备投资假定发生在期初,当年即投产运营。
假定国民经济评价产出物的影子价格与市场销售价格一致;经营成本包含国家环保部门规定的每年收取200万元的排污费;企业排放的污染物对国民经济的实际损害为销售收入的10%。经营成本其余部分及国内运输费用和贸易费用的国民经济评价的计算结果与财务评价相同。
目前,年销售收入为3200万元,年经营成本为2400万元。市场研究表明,该产品还可以在市场上销售5年,5年后停止生产。第5年末进口设备残值为50万元,并可以此价格在国内市场售出。设备的国民经济评价影子价格与市场出售价格相同。假设财务基准收益率为10%,社会折现率为10%,美元兑人民币官方汇率为1:7.92,影子汇率换算系数为1.08。已知:(P/A,10%,5); 3.7907,(P/F,10%,5)=0.62092。
问题:1.用财务净现值法,从财务评价的角度分析此项目是否可行
2.用经济净现值法,从国民经济评价的角度分析此项目是否可行

阅读理解

阅读理解。

     Do I really need a helmet just to ride to class?

     First, ask your physics professor what can happen to a head dropped from the normal height where you

ride, say about 5 feet up, when it hits the walkway? He will tell you about the forces the head can experience

from that drop height. Bike helmets are tested in a two-meter drop, a little higher, but that five feet is all the

force you need to mess up your brain. You don't need forward speed at all, although it can make it worse.

     Then think about accidents that happen when you ride on campus. Have you had near-collisions (碰撞)

or actual collisions with pedestrians as the students change class? Do you ever hurry to get to class and take

little chances? Have you ever seen a patch of ice or sand on a campus sidewalk? We would bet that you know

more risk factors than we do.

     And what do the statistics say? There are 800 people killed on bikes, and a half million, more or less

injured, in the US every year. Nobody keeps track of how many of those were on a campus. But we do know

that you are making a major investment in yourself for a lifetime of good returns. People with head injuries

can remember how much more they were able to do mentally before the crash, and that hurts long after other

parts heal (愈合). The effects can last forever. At your age you are just beginning to realize how much

pleasure in life comes from being experienced, smart and educated. You don't want to take a chance with that.

It means a lot to you.

     Helmets are cheap at Wal-Mart or Target, and the cheap ones work fine if you fit them carefully. It really

won't mess up your hair much in a short ride. Give it a try. 

1. The aim of this text is probably______.

A. to introduce a way to protect one's head

B. to remind students to wear helmets while riding

C. to persuade students to buy more helmets at Wal-Mart

D. to warn students against bicycle riding because of danger

2. Helmets are necessary for bicycle riders on campus because _____.

A. they will meet with an accident sooner or later

B. the brain will be protected during an accident

C. their hair will not be messed up in a short ride

D. they will have to fight against the students from other classes

3. In paragraph three, the writer mainly wants to tell us that _____.

A. riding bicycles is too dangerous

B. the traffic on the campus is often out of order

C. the number of bicycles on campus should be limited

D. it is difficult to avoid accidents while riding bicycles on campus

4. The "major investment" refers to the money for _____.

A. a safer bike

B. bike accidents

C. a helmet

D. a campus insurance

5. This passage would probably appear in the part of ______ on a website.

A. Science

B. News

C. Education

D. gym