Chứng minh A = 3x . (3x - 1) . (3x + 1) - (3x - 2).($9x^{2}$ + 6x + 4) + x . (x - 5) - $(x - 4)^{2}$ không phụ thuộc vào biến x. Có triển khai hằng đẳng thức nữa, làm hộ cmn.

Tìm giá trị lớn nhất M và giá trị nhỏ nhất m của hàm số y= 3- 2|sin4x|.

Chọn một đoạn văn từ 8- 10 câu, phân định các thực từ trong đoạn

despite being tired ,i still went to school. ( đổi sang although, giúp mk vs)

Mk cần gấp ạ,đề bài là chuyển sang câu bị động

33. They haven’t decided the exact time of the match yet.----→ The exact time of the match _____ 34. He hasn’t chatted with his classmates through the Internet for a long time.→ It is _____ 35. I would like you to help me put the chairs away.→ Would you mind _____ 36. My friend enjoys reading books. He particularly enjoys reading thrillers.→ The kind of books which _

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 1 to 7. Imagine the busy streets of New York City, an enormous place with millions of people. Everyday, the streets are congested with people going about their daily lives. Now imagine a small robot in the middle of all of those people rolling down a busy sidewalk. Most people would not even notice the ten– inch smiling robot, called a Tweenbot, rolling along the street. This strange machine may interest some people, while others would ignore it completely. A researcher interested in studying how helpful people really are uses such robots in her experiments that take place on the streets of New York. The Tweenbots experiment is the idea and creation of Kacie Kinzer. Kinzer’s idea was to make a robot that could navigate the city and reach its destination only if it was aided by pedestrians. Tweenbots rely on the kindness of warm–hearted strangers. Made simply of cardboard, wheels, and a device to turn the wheels, the Tweenbots face many dangers on the city streets. They could be run over by cars or smashed by careless kids. Kinzer thought her little robots might even be seen as some kind of terrorist device. The only real protection a Tweenbot has is its friendly smile. In addition to that, each of Kinzer’s robots is fitted with a flag that displays instructions for the robot’s destination. The only way these robots will reach their final point is if someone lends them a hand. Tweenbots are essentially a social experiment aimed at providing people a chance to show how caring they are. On a daily basis, people in New York City are often in a hurry to get around. However, the Tweenbots, through their inability to look after themselves, took people out of their normal routines. The people who noticed the helpless little robots were actually interested in helping the Tweenbots find their way home. Tweenbots move at a constant speed and can only go in a straight line. If one was to get stuck, or was going in the wrong direction, it would be up to strangers to free it or turn it in the right direction. Surprisingly, no Tweenbot was lost or damaged, and each one arrived at its target in good condition. In fact, most people treated the robot in a gentle manner, and some even treated it as though it were a small living being. Even if you were in a rush to go somewhere, would you stop and help a Tweenbot successfully reach its destination? Question 1: What is this reading about? A. A place to buy robots B. A new kind of toy C. An experiment D. An interesting idea for the future Question 2: What is a Tweenbot? A. A person from New York City B. A ten–inch smiling robot C. A pedestrian D. A terrorist device Question 3: The word “congested” in paragraph 1 is closest in meaning to . Thích Tiếng Anh – thichtienganh.com – Website học Tiếng Anh miễn phí! Thích Tiếng Anh | thichtienganh.com sưu tầm và biên soạn 2 A. flocked B. secluded C. stuffed D. crowded Question 4: How did a Tweenbot get to its final destination? A. With the help of other Tweenbots . B. With the help of kind pedestrians on the street. C. With the help of Kacie Kinzer. D. With the help of other robots in New York City. Question 5: The word “is fitted with” in paragraph 2 is closest in meaning to . A. is armed with B. is embedded with C. is supplied with D. is assembled with Question 6: Which of the following statements is NOT correct? A. Most Tweenbots arrived at their destination damaged or broken. B. Most people treated the Tweenbots in a gentle manner. C. Tweenbots could not navigate the city on their own. D. Tweenbots move at a constant speed and can only go in a straight line. Question 7: What can be inferred about the Tweenbot? A. They were useful for research. B. They were ignored by most people. C. They were helpful for pedestrians . D. They did not work as planned. Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions. Question 8: , I decided to stop trading with them. A. Despite of the fact that they were the biggest dealer B. Though being the biggest dealer C. Being the biggest dealer D. Even though they were the biggest dealer Question 9: Mr Pike English at our school for 20 years before he retired last year. A. was teaching B. has been teaching C. is teaching D. had been teaching Question 10: I used to reading comics, but now I’ve grown out of it. A. take a fancy with B. keep an eye on C. get a kick out of D. kick up a fuss about

the concert..........................(start) at 7 p.m ...................................(she-visit) her grandma very often? sandra.......................(lend) her brother $200 so far My parents .......................(go) to the theater yesterday evening we ............................. ( go /not) to school on sundays mary.................... (lose) her hat for 2 days

Một vị phụ huynh học sinh hỏi thầy giáo: "Thưa thầy, trong lớp có bao nhiêu học sinh?" Thầy cười và trả lời:"Nếu có thêm một số trẻ em bằng số hiện có và thêm một nửa số đó, rồi lại thêm 1/4 số đó, rồi cả thêm con của quý vị (một lần nữa) thì sẽ vừa tròn 100". Hỏi lớp có bao nhiêu học sinh?

Air pollution occurs when wastes dirty the air. People produce most of the wastes that cause air pollution. Such wastes can be in the form of gases or particles of solid or liquid matter. These substances result chiefly from burning fuel to power motor vehicles and to heat buildings. Industrial processes and the burning of garbage also contribute to air pollution. Besides, there are other polluting substances that exist naturally into the air. They include dust, soil particles, and naturally occuring gases. The rapid growth of population, industry and the increasing use of automobiles and airplanes have made air pollution a serious problem. The air we breathe has become so filled with pollutants that it can cause health problems. It also harms plants, animals, building materials, and fabrics. 13. All of the wastes that people produce cause air pollution. 14. Soil participles are natural pollutants. 15. Polluted air has a harmful influence on people, plants and animals. 16. Air pollution has become a serious problem due to the increasing population and industry. 17. The word “they” in line 5 refers to: A. motor vehicles B. natural pollutants C. Industrial processes D. buildings 18. What does not contribute to air pollution? A. The burning of garbage B. industrial processes C. motor vehicles D. the natural existence of oxygen in the air