问题 解答题

已知四个数,前三个数成等差数列,后三个数成等比数列,中间两数之积为16,前后两数之积为-128,求这四个数.

答案

设所求四个数为-aq,,aq,aq3

则由已知得()(aq)=16,                 ①

)(aq3)=-128,                         ②

由①得a2=16,∴a=±4.

由②得2a2q2-a2q4=-128.

将a2=16代入得q4-q2-8=0.

解得q2=4,∴q=±2.

因此所求的四个数为-4,2,8,32或4,-2,-8,-32.

题中已知条件很多,涉及到的数共4个,存在着几种关系.合适地设四个数为解决本题的关键.设好未知数后,根据关系列出表达式,然后求解即可.

阅读理解

James is a good student and he has lots of friends,but he also has a problem.Some older boys are bullying(欺负)him at school.James is very unhappy and he doesn't know what to do about it.Here are some suggestions to him and other teenagers in this situation.

Don't feel worried.It's not your fault(过错)! Being bullied can make you feel very lonely and angry,but you are not alone.Don't feel that you have to hide the problem.You should find a person you can trust,and tell them.It might be your teacher,your parents,or even your friend's parents.After you tell someone,you will get some support and feel some relief(解脱).

Speaking to an adult might make you nervous,but here are other things you can do.Some people express their feelings more easily on paper.Write a letter to someone or keep a diary.Include all the details(细节)about what the bullies do, as well as when and where the bullying happens.You can use it as proof to show what is going on.And it is a wonderful idea to show your letter or diary to a teacher or another responsible adult.Then the bullies will feel very afraid if their names appear in a letter!

Also,don't show you are sad and don't try and fight with the bullies. You could get in trouble yourself. Ignore them and just walk away. The bullies will soon stop.

小题1:What do you think the text is trying to tell us?

A.What to do about being bullied.

B.How to be a good student at school.

C.What to write well in a diary.

D.How to give suggestions to teenagers.小题2:You'd better go and find a person you can trust and ____.

A.know what happens

B.learn from them

C.ask for help

D.make them lonely小题3: If you remember and follow the suggestions above, ____.

A.nobody will speak to the bullies

B.everybody will feel some relief

C.someone will express their feelings

D.the bullies will soon stop小题4:What does the underlined word "ignore" mean in the text?

A.take no notice of

B.take care of

C.make full use of

D.get more help from

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