Cho biểu thức: A = (x/x^2-4-4/2-x+1/x+2):3x+3/x^2+2x

a) Tìm điều kiện xác định của A và rút gọn biểu thức A; 

b) Tính giá trị của biểu thức A khi |2x-3|-x+1=0

c) Tìm giá trị nguyên của x để A nhận giá trị nguyên.

Cho biểu thức: A=(1-2x/2x+2x/2x-1+1/2x-4x^2):(3/x^2-2x^3) với x khác 0 và 1/2 a) Rút gọn biểu thức A.

b) Tìm giá trị của x để biểu thức A đạt giá trị lớn nhất.

Cho hình vuông ABCD. Gọi E là trung điểm CD, F nằm trên cạnh BC sao cho BF=3FC. Chứng minh EF=1/2 AE.  (gợi ý: Gọi I là trung điểm của BC, c/m EF =1/2 DI và DI = AE)

Viết đoạn văn sử dụng should/ shouldn't/ have to để khuyên người nước ngoài nên làm gì để tìm hiểu văn hóa Việt Nam.

Chứng minh rằng trung điểm các cạnh hình thang cân là các đỉnh của hình thoi.

Complete these sentences with the correct form of the verbs
1. He wanted to know where I ....................................................... for the last few years. (live)
2. I warned her ....................................................... too near the cliff edge. (not go)
3. I told them ................................................ they were in the right part of the train. (check)
4. We agreed that I ....................................................... them a few days later. (see)
5. He begged her ................................................. him some money, but she refused. (give)
6. The expression on his face told me that I ....................................................... late. (be)
7. We decided that the computer .................................................... switched off. (have to be)
8. Your parents want to know if you ....................................................... a good time at the
moment. (have)
9. The publishers have told me that they ....................................................... my book. (not going
to accept)
10. He indicated that he ....................................................... by nodding his head. (agree)
11. They shouted that they ....................................................... cross the river and that they
....................................................... back to the car. (cannot / going to go)
12. They asked me ........................................ anything but just ...........................................
quietly. (not say / listen)
13. She asked when the plane .................................................................. the night before and
whether it ....................................................... direct from Brussels. (arrive / come)
14. He asked whether I ....................................................... to Dr. Jones when I was in hospital.
(talk)

Read the interview with a journalist. Then complete the article. A: What mistakes do people make when they write e-mails? B: Often they’re too vague. A: Are there any other common mistakes? B: Yes, they ask for information they don’t need - this wastes everyone’s time. A: So how can we make a good first impression in an e-mail? B: Be specific about the subject - and for goodness’ sake, don’t use words like ‘hello’ on the subject line! A: How formal should we be? B: Be as formal or casual as the person who sent you the e-mail. A: Do people send too many e-mails? B: Yes. E-mails are for giving and confirming information. Don’t use them for negotiations. A: Could you tell me why companies monitor their employees’ e-mails? B: Many reasons. Sometimes they want to be sure that employees aren’t giving secrets away to competitors. Writing Emails I asked Hamish Elphinstone (17) ........................................................................... when they wrote e- mails and he replied that people were often unclear about what they wanted. I asked him (18) ........................................................................... any other common mistakes and he said that people wasted time by asking for information they didn’t need. Next, I asked him (19) ........................................................................... a good first impression in an e- mail. Hamish told me (20) ........................................................................... specific about the subject and (21) ........................................................................... words like “hello” on the subject line. On the subject of style, I asked Hamish (22) ......................................................................... in an e-mail. His suggestion was that we should be as formal as the sender of the original e-mail. Then we discussed how to use e-mail most effectively. I enquired (23) ............................................ ............................................ too many emails and not surprisingly, he said that, yes, they did. He went on to say that e-mails were for giving and confirming information and he told me (24) ............................... ............................................ them for negotiations. Finally, I asked him (25) ........................................................................... their employees’ e-mails. Apparently, some businesses are concerned that employees might be selling secrets to competitors.