How many students are there in herclass ==>
ai giúp mink giải bài này với mink nhgix mãi ko ra ai giải đc mink xin cảm ơn nha
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Bạn có thể nhận thấy rằng mỗi phân số trong dãy là tổng của phân số trước đó và một phân số có tử số là 1 và mẫu số tăng dần từ 2 đến 56. Vì vậy, tổng của dãy phân số này chính là số lượng các phân số có tử số là 1, trừ đi 1 (vì phân số đầu tiên là 1/2, không phải 1/1).
Vậy, tổng của dãy phân số này là 5.
các bạn ơi giúp mink bài 3 với nha mink cần gấp tối nay rồi !
giúp mink với nha mink cảm ơn nhìu lắm
\(A=2x^2+8x-9x-36+a+36\)
Để A chia B dư là -2 thì a+36=-2
hay a=-38
I. Circle the best option (A, B, C or D) to complete the passage below: (1.0pt)
Thirty years ago in Vietnam, very few people had TV sets. These TV owners were very (1)____________. After dinner, their neighbors (2)_____________both inside and outside their houses. Some watched through the windows. All evening, (3)____________ sat and watched the black and white programs. Times have changed. Today, many families have a TV set. They sit and watch (4) _____________ their own living rooms.
1. A. important B. wonderful C. expensive D. popular
2. A. gathers B. gathered C. gather D. to gather
3. A. he B. she C. they D. I
4. A.in B. at C. on D. to
II. Read the passage carefully and then answer the questions: (2.0pts)
A French oceanographer, Jacques Cousteau (1910 - 1997), invented a deep-sea diving vessel in the early 1940s. In the vessel, he could explore the oceans of the world and study underwater life. Now we can explore the oceans using special TV cameras as well. We can learn more about the undersea world thanks to this invention.
Questions:
1. When was Jacques Cousteau born?
________________________________________________________________
2. How old was he when he died?
________________________________________________________________
3. What did he invent?
________________________________________________________________
4. Can we learn more about the undersea world thanks to Jacques Cousteau's invention?
________________________________________________________________
PART C: VOCABULARY & GRAMMAR
I. Circle the word that has different stress from others: (0.5pt)
1. A. aquarium B. material C. appointment D. temperature
2. A. adventure B. detective C. cucumber D. invention
II. Circle the word whose underlined part is pronounced differently from others: (0.5pt)
1. A. helped B. rented C. talked D. watched
1. A. baseball B. ask C. participate D. basketball
III. Circle the word or phrase (A, B, C or D) that best completes each sentence: (1.5pt)
1. She smiled ___________ me in a friendly way when she saw me.
A. with B. to C. of D. at
2. We ___________ our grandparents next week.
A. visit B. will visit C. visited D. to visit
3. How ___________ is the blue hat? It's 50,000 dong.
A. far B. many C. old D. much
4. What about ___________to school every morning?
A. going B. go C. to go D. went
5. The nurse __________ Lan's temperature yesterday.
A. will take B. took C. is taking D. takes
6. I usually ___________football.
A. will play B. is playing C. play D. played
PART D: WRITING
I. Rewrite each sentence so that it has the same meaning as the first one: (1.5pts)
1. How tall are you?
=> What__________________________________________________________?
2. Nam is a bad swimmer.
=> Nam swims _____________________________________________________
3. What is wrong with him?
=> What is the______________________________________________________?
4. You ought to take morning exercise
=>You should _____________________________________________________
5. I prefer living in the city.
=> I Prefer __________________________________________________________
II. Complete the following sentences with the words given:(1.0pt)
1. Let's/ buy a papaya.
=>_________________________________________________________________
2. Are you free/ Thursday?
=>_________________________________________________________________
II. TỪ VỰNG, NGỮ PHÁP
Chọn một đáp án đúng nhất trong ngoặc để hoàn thành câu.
6. We enjoy..... "Tom and Jerry" films in the evenings.
A. watching B. watched C. watch D. to watch
7. Where..... they..... their summer vacation next year?
A. do/ spend B. will/ spend C. did/ spend D. are/ spend
8. Look! The students..... badminton in the school yard.
A. play B. played C. are playing D. A&B
9. My sister..... a new book yesterday morning.
A. will buy B. is buying C. buys D. bought
10. Nobody..... him very well because he is new here.
A. know B. knows C. knowing D. A&C
11. Don't forget..... a dictionary for me, Nam.
A. buy B. buying C. to buy D. bought
12. She was busy..... her homework.
A. doing B. to do C. did D. A&B
13. We can't go out now because it..... outside.
A. rained B. rain C. rains D. is raining
14. - A: Oh, I don't like bananas. - B:......
A. I don't, either B. I do either C. Neither, do I D. A&C
15. He was only fourteen, but he is..... his father.
A. as tall as B. taller C. tall than D. as taller than
16. These mangoes are not ripe, and..... are those bananas.
A. So B. Either C. Neither D. Both
17. These are their shoes here and those are..... over there.
A. we B. our C. ours D. us
18. Nam is better..... English, but he is worse..... math than I am.
A. at/in B. in/at C. in/in D. at/at
19. His new shoes are different..... mine, but his new shirt is similar..... mine.
A. to/from B. from/to C. with/to D. from/from
20. It is easy..... a bike, but it's difficult..... a car.
A. to ride/ to drive B. to drive/ to ride C. riding/ driving D. driving/ to ride
21. It often..... me 15 minutes to go to school by bike.
A. takes B. gets C. gives D. has
22. Of all schools in this town, mine is.....
A. the largest B. the larger C. the large D. the more large
23. He wants to learn..... to use the computer.
A. what B. how C. why D. where
24. Mai looks..... in her new dress.
A. more beautifully B. beautifully C. more beautiful D. beauty
25. We can learn more..... the undersea world thanks..... Jacques Cousteau's invention.
A. about/ on B. about/ to C. on/ to D. on/ for
III. ĐỌC HIỂU, VIẾT
Bài 1 : Điền vào mỗi chỗ trống được đánh số bằng một từ thích hợpcho sẵn.
popular - small - pair - to - are - strongest - free
Today, badminton becomes a very (26)..... sports activity. It spreads quickly from the city (27)..... the countryside.People need only a (28)..... of rackets, a shuttlecock, a net and a (29)..... piece of land to play the game. Two or four players hit the shuttlecock over the net with their rackets. People can play badminton in their (30)..... time or in a competition. Now, there (31)..... many badminton competitions andeven a World Cup. One of the (32).....countries in badminton is Indonesia.
Bài 2: Tìm một lỗi sai trong số A, B, C hoặc D ở mỗi câu sau.
33. Children are usually scared for seeing the dentist.
A B C D
34. The teacher told him to spend a little time to play video games.
A B C D
35. It took me two hours doing my homework last night.
A B C D
36. After the neighbor repaired the skirt, it looked beautifully.
A B C D
Bài 3: Viết lại câu bằng từ cho sẵn sao cho giữ nguyên nghĩa với câu đầu.
37. What a luxurious car!
How...................................!
38. It takes me an hour to do my homework every evening.
I spend..................................
39. No one can run faster than me.
I am....................................
40. Do you have a better refrigerator than this?
Is this...................................
Trên mạng thiếu gì cái này mình lấy trên mạng nhé nên hơi dễ nhé :v Còn đề lớp 7 thì mình ko có :))
Bài 4:
a: Ta có: \(-\left|x+1.1\right|\le0\forall x\)
\(\Leftrightarrow-\left|x+1.1\right|+1.5\le1.5\forall x\)
Dấu '=' xảy ra khi x=-1,1
b: Ta có: \(-4\left|x-2\right|\le0\forall x\)
\(\Leftrightarrow-4\left|x-2\right|+10\le10\forall x\)
Dấu '=' xảy ra khi x=2
Đặt A=1/10+1/11+1/12+...+1/99+1/100 (91 số hạng)
A=1/10+(1/11+1/12+...+1/99+1/100)
Vì 1/11>1/100
1/12>1/100
..................
1/99>1/100
Suy ra: A>1/10+(1/100+1/100+...+1/100) (90 số hạng 1/100)
A>1/10+90/100
A>1
Vậy 1/10+1/11+1/12+...+1/99+1/100>1
Nếu đồng ý vs câu trả lời của mk thì k cho mk nhé! Thanks!
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