1101001₂ = ?₁₀

Vật chuyển động thẳng trên trục Ox từ điểm có tọa độ x1= 5cm đến điểm x2 = - 15cm trong khoảng thời gian 2s,  tính độ biến thiên tọa độ, vận tốc trung bình, quãng đường  đi đc và tốc độ trung bình trong khoảng thời gian đó.

Giúp với mình tick cho

21. I felt bad ________ him with all the washing up after the meal, but I had to get back to work.
A. to leave    B. leaving         C. leave
22. It wasn’t the ________ holiday I’ve ever had, but it was certainly the ________.
A. cheapest ... most relaxing      B cheapest ... relaxingest       C. most cheap ... most relaxing
23. Some people in the factory were found to be earning ________ a dollar a day.
A. as little as        B. as few as           C. so little as
24. When I started to put up the shelves, I discovered that it wasn’t ________ I’d first thought.
A as easy job as      B. as easy a job       C. as easy a job as
25. If you ________, maybe I can help you solve it.
A. explain me the problem B. explain the problem to me C. explain the problem for me
26. I’ve been doing lots of training in the gym to prepare ________ the marathon.
A. me for running       B. myself to run        C. myself for running
27. Considering that we don’t have many interests in common, we get along quite well.
A. with each another    B. with each other     C. for each other
28. After being away for so long, I’m really looking forward ________ back home.
A. to getting     B. getting     C. to get
29. I often don’t have time to eat a proper lunch, so I ________ just a banana.
A. make to do with     B. make do for     C. make do with
30. I waited ________ before going to work.
A. for the post arriving      B. for the post to arrive    C. to the post to arrive
31. In 1927, Belgian-born Georges Lemaitre published his explanation of the creation of the universe ________ became known as the Big Bang theory.
A. which     B. , which     C. that
32. As warm air rises, it mixes with cooler air above and cools to a point ________ it stops rising.
A. where            B. that      C. which
33. The police held three men for questioning, all ________ denied any part in the robbery.
A. of whom       B. whom        C. of which
34. The office block now ________ in the city center will be the highest in the country.
A. being built        B. building      C. built
35. The last person ________ the room should switch off the lights.
A. left      B. leaves      C. to leave
36. I’m looking for a relatively cheap digital camera, ________ and relatively cheap.
A. is easy to use     B. easy using     C. easy to use
37. I was just about to ring the bell ________ the door opened.

A. as      B. when          C. while
38. Football is the most popular sport in the country ________ more people pay to watch it than any other.
A. inasmuch as     B. inasmuch that      C. as much as
39. She avoided telling Alan what she thought of his painting ________ offend him.
A. not     B. so not to     C. in order not to
40. If I ________ more time, I’d like to learn to play a musical instrument.
A. will have      B. would have      C. had

Giúp mình với

11. My parents gave me the money for the car. I ________ have afforded to buy it myself.
A. couldn’t    B. can’t     C. mustn’t
12. I ________ have listened to your advice and started out before the rush hour.
A. must     B. had better     C. ought to
13 Today’s Times ________ reporting that the number of people emigrating from the country ________ risen to record levels.
A. is ... have     B. is ... has     C. are ... have
14. ________ found that most people listen to the radio for longer than they watch television.
A. A recent research has      B. Recent research has         C. Recent researches have
15. Scientists are predicting that Britain will have ________ as cold as Canada’s within a hundred years unless global warming is brought under control.
A. the climate      B. climate      C. a climate
16. ________ welcome the decision to turn street lights off at midnight.
A. Not all residents in the area       B. All residents in the area don’t      C. Not any residents in the area
17. He had a neat beard and a small gold earring in ________ ear.
A. every         B. each of       C. each
18. Although the villagers were very poor, they were always happy to share with us ________ food they had.
A. the few      B. little     C. the little
19. The new magazine for teenagers is ________.
A. weekly to be published     B. to be weekly published     C. to be published weekly
20. The conference has been a great success, and I’d like to thank all the ________.
A. people involved    B. very involved people       C. involved people

10 câu trắc nghiệm giúp mình với

1. I ________ that Dave’s put his house up for sale.
A. ’m seeing      B. see     C. ’ve been seeing
2. John ________ me three times already this morning, and I’ve only been at work for an hour.
A. had phoned       B. phoned      C. ’s phoned
3. When I said I’d visit them in New Zealand, I ________ how expensive the airfare would be.
A. haven’t realized      B. hadn’t realized      C. hadn’t been realizing
4. If you give me your coat, I ________ it up for you.
A ’ll hang      B. ’m going to hang     C. ’m hanging
5. Give me a ring when you ________ back home.
A. get     B. will get      C. are getting
6. The peace talks ________ today, but last weekend the meeting was postponed indefinitely.
A. were to start     B. are starting    C. were to have started
7. Nixon fell off his bike early in the race but ________ continue after receiving medical treatment.
A. can      B. could      C. was able to
8. The blue whale ________ grow up to 30 meters long.
A. might      B. can     C. could
9. When the snow blocked the road, motorists ________ abandon their cars and walk.
A. have to     B. must      C. had to
10. Have you eaten all the cake? You ________ have left some for me!
A. might     B. may      C. can

Cho A = \(\dfrac{1}{\sqrt{x}-2}\)   (x ≥ 0; x≠4)

Với x là số chính phương, hãy tìm giá trị nhỏ nhất, giá trị lớn nhất của A.

Giúp mình với!

chất gì nhiệt phân ra ba sản phẩm trong đó có 2 chất là O2 và H2O