Các bạn ơi giúp mình bài a với b nha:
a)
b)
bài 1: cho a,b,c>0 CMR
\(\frac{1}{a}+\frac{1}{b}>=\frac{4}{a+b}\)
các bạn ơi giúp mình bài này khó quá. nhanh nha tối mình đi học rồi. các bạn ơi giúp mình đi mà. Hinh nhu de bai la the nay cac ban giup minh nha
Với a,b >0.Ta có: \(\frac{1}{a}+\frac{1}{b}\ge\frac{\left(1+1\right)^2}{a+b}=\frac{4}{a+b}\left(đpcm\right)\)
Dấu = xảy ra khi và chỉ khi a=b
Cho a,b,m,n thuộc N . So sánh a^n với a^m ( đây là bài tập nâng cao )
Các bạn lớp 6 ơi ! Các bạn giúp mình với tối nay là mình cần rồi !
bạn nào nhanh tay trả lời mình tick cho nhé !
Ta có 3 trường hợp :
+ TH 1 : Nếu n > m thì a^n > a^m
+ TH 2 : Nếu n < m thì a^n < a^m
+ TH 3 : Nếu n = m thì a^n = a^m
Chúc bạn hok tốt nhé!!
các bạn ơi giúp mình với mai mình hok rồi
Tìm số A thuộc N biết ƯCLN (a, 96 ) = 16 và a < 96
cố giúp mình nha các bạn mình cảm ơn trước
Lời giải:
a ϵ N, Do U(a, 96) = 16 và a < 96 nên ta có:
\(\begin{cases}a=16.k\left(k\in N\right)\\96=16.6\end{cases}\) → (k, 6) = 1 và k < 6 → k ϵ {1; 5}
Với k = 1 => a = 16.1 = 16Với k = 5 => a = 16.5 = 80Đáp số: a = 16 hoặc a = 80
Các bạn ơi, giúp mình với: Tìm a và b biết: a + b = b - a
Với a=0 ; b=0 thì a+b=b-a=0
Với \(a\ne0;b\ne0\)thì a+b>b-a
Các bạn ơi giúp mình bài này với, 5 bạn trả lời đúng nhanh nhất mình sẽ v cho nha!
FINAL TEST 2
I. Find the word which has a different sound in the underlined part.
1. A. can B. star C. bag D. that
2. A. far B. plant C. plan D. hat
3. A. plastic B. start C. stand D. land
4. A. smart B. channel C. cancer D. thanks
5. A. cart B. heart C. card D. animal
II. Find one odd word for each question, and then read them aloud.
6. A. plastic B. glass C. metal D. bag
7. A. reduce B. repeat C. reuse D. recycle
8. A. bottle B. bag C. bin D. paper
9. A. refillable B. reusable C. recycled D. repair
10. A. floods B. rubbish C. litter D. garbage
III. Choose the correct answers. of trees.
11. If we waste paper, we will save a lot of trees.
A. repeat B. recycle C. rewrite D. remake
12. If we plant more trees in the schoolyard, the school will become a place.
A. greener B. darker C. dirtier D. more polluted
13. "Why do you often forget to the lights when you go out of the classroom?"
A. turn on B. turn off C. close D. shut down
14. "What can we do air pollution?"
A. reduce B. to reduce C. reducing D. to reducing
15. You can save money while shopping by only buying you need.
A. what B. it C. this D. that
16. "Reduce, reuse, recycle" is said to encourage people to waste less, by using less and using things again, in order to the environment .
A. harm B. damage C. pollute D. protect
17. Please collect all the recyclable materials, and take them to the factory.
A. recycle B. recycled C. recyclable D. recycling
18. This newspaper is made of paper.
A. recycle B. recycled C. old D. waste
19. If we all use bags, we'll help the environment.
A. new B. cheap C. reusable D. reduced
20. These three Rs . reduce, reuse, and recycle
A. stand up B. stand for C. ask for D. means
21. If there is a rubbish bin in every class, the classroom will become .
A. harmful B. lighter C. dirtier D. cleaner
22. "Don't throw rubbish into the river because you will make it ."
A. greener B. dirty C. cleaner D. fresher
23. If we use paper, we will save a lot of trees.
A. fewer B. less C. more D. much
24. You should put the food in a reusable box plastic bag.
A. by B. instead of C. because of D. without
25. If people turn off all electric appliances in one hour all over the world, they can save lots of .
A. electric B. electrical C. electrician D. electricity
26. It is a good idea to our clothes with our friends or cousins.
A. change B. swap C. turn D. send
27. Next week our class is having a discussion about finding ways to reuse old items before throwing them away.
A. interested B. surprising C. useless D. creative
28. If you have old clothes, will you give them to those ?
A. needs B. to need C. for needing D. in need
29. My brother and I will give last year's clothes to instead of throwing them away.
A. shop B. people C. charity D survey.
30. "Do you think we should put a bin in every classroom in order to keep it clean?"
A. reusable B. recycled C. recycling D. recyclable
IV. Write conditional sentences from these statements.
31. We will plant more trees. The air will be fresher.
If ___________________________________________ .
32. We will use fewer cars. We will reduce pollution.
If ___________________________________________
33. We will cycle to school every day. We will keep fitter.
If ___________________________________________
34. We will use recycled products. We will save money.
If ___________________________________________
35. People will throw rubbish into the right bin. They will keep the environment clean.
If ___________________________________________
36. We will turn off the tap when brushing the teeth. We will save a lot of water.
If ___________________________________________
37. People will travel more by public transport. The harmful gases in big cities will be reduced.
If ___________________________________________
38. We will start at 6.00. We will arrive there before noon.
If ___________________________________________
39. The boy eats so may green apples. He will be ill.
If ___________________________________________
40. We will use reusable bags for shopping. We will reduce waste.
If ___________________________________________
V. Choose the word or phrase among A, B, C or D that best fits the blank space in the following passage.
Last month Lan's father (41) her to a glass factory. They visited the recycling workshop where the broken glass was smashed (42) small pieces, and the glass was washed with a particular detergent liquid. After that, it was dried up and mixed (43) some chemicals. The mixture was put into a very (44) temperature furnace to melt into liquid. The workers in the factory used long pipes (45) the liquid into a variety of shapes. All the glassware looks nice. Lan was very impressed by the journey.
41. A. asked B. took C. told D. gave
42. A. under B. into C. in D. on
43. A. in B. of C. up D. with
44. A. high B. strong C. low D. weak
45. A. change B. to make C. to blow D. to have
VI. Read the following passage, and then answer the questions below.
Every day of the year throughout the world, about twenty million paper bags and the newspapers are screwed and thrown away. Making paper requires a lot of wood pulp and the work of millions of workers. Many countries have had plans to recycle waste paper to save money and labor. In countries where there is the cooperation of the public, paper mills recycle as much as sixty percent of waste paper. Their simple work is to take away the ink, crush it up and make it into pulp again. For every ton of recycled newsprint, twelve trees can be saved. We can insist that the more paper people save, the more trees are preserved.
46. How many paper bags and newspapers are screwed and thrown away every day?
___________________________________________
47. What have many countries done to save money and labor in making paper?
___________________________________________
48. What percentage of waste paper is recycled with the help of the public?
___________________________________________
49. What do the paper mills do to reuse waste paper?
___________________________________________
50. How many trees can be saved for every ton of recycled newsprint?
___________________________________________
Một ô tô đi từ A đến B với vận tốc là 50 km/giờ , đi từ B về A với vạn tốc 60 km/giờ , thời gian lúc về kém thời gian lúc đi là 18 phút . Hỏi quãng đường từ A đến B dài bao nhiêu km ?
Các bạn ơi giúp mình giải bài toán này với và giúp mình làm có câu lời giải , phép tính hẳn hoi nhé . Mong các bạn giúp mình làm bài này với nhá .
Thanks you , thanks you ,thanks you ,thank you , thanks you !!!
Thời gian đi tỉ lệ nghịch với vận tốc.
Tỉ lệ vận tốc đi và về là: 50/60 = 5/6.
Thời gian đi và về sẽ tỉ lệ nghịch với 5/6, tức là 6/5.
Gọi thời gian đi là 6 phần, thời gian về sẽ là 5 phần. Hiệu số phần là: 6 - 5 = 1 (phần).
Hiệu thời gian là 1 phần ứng với 18 phút = 0,3 giờ.
Vậy 1 phần = 0,3 giờ
=> Thời gian đi là: 0,3 x 6 = 1,8 giờ
Thời gian về là 0,3 x 5 = 1,5 giờ.
Quãng đường AB là 1,8 x 50 = 90 km
Thời gian đi tỉ lệ nghịch với vận tốc.
Tỉ lệ vận tốc đi và về là: 50/60 = 5/6.
Thời gian đi và về sẽ tỉ lệ nghịch với 5/6, tức là 6/5.
Gọi thời gian đi là 6 phần, thời gian về sẽ là 5 phần. Hiệu số phần là: 6 - 5 = 1 (phần).
Hiệu thời gian là 1 phần ứng với 18 phút = 0,3 giờ.
Vậy 1 phần = 0,3 giờ
=> Thời gian đi là: 0,3 x 6 = 1,8 giờ
Thời gian về là 0,3 x 5 = 1,5 giờ.
Quãng đường AB là 1,8 x 50 = 90 km
Các bạn ơi giúp mình viết :
a) Viết tên 5 địa danh ở nước ngoài
b) Viết tên 5 người ở nước ngoài
Giúp mình với , mai mình phải nộp bài cho cô giáo rồi !
- Tên người : Lép Tôn-xtôi, Mô-rít-xơ, Mát-téc-lích, Tô-mát Ê-đi-xơn, Lê-o-na-đô-đa Vanh-xi.
- Tên địa lí: Hi-ma-lay-a, Đa-nuýp, Lốt Ăng-giơ-lét, Niu Di-lân, Công-gô.
cho mk hỏi là viết phiên dịch ra tiếng việt hay viết bằng tiếng anh
Giúp mình mấy bài cuối với các bạn ơi :))
Choose the correct answers.
1. If that hat costs much, I a small one.
A. would have bought B. will buy
C. bought D. would buy
2. If you more carefully, you would not have had so many accident.
A. drive B. drove C. had driven D. has driven
3. “Tom more races if the trained hard.” The man said.
A. would win B. wins C. would have won D. would be winning
4. If I spoke English, my job a lot easier.
A. was B. were C. will be D. would be
5. “If you feel like a chat, .” David said to me.
A. phone to me tonight B. will you phone me tonight
C. phoned me tonight D. phone me tonight
6. I will lend them some money if they me.
A. ask B. will ask C. asked D. had asked
7. If we had known who he was, we him to speak at our meeting.
A. would have invited B. have invited
C. will invite D. would invite
8. “If you too much junk food, you would be a lot fitter.” Mother said.
A. ate B. didn’t eat C. didn’t ate D. had eaten
9. If I enough money. I would buy a house.
A. had B. had had C. will have D. have
1. If that hat costs much, I a small one.
A. would have bought B. will buy
C. bought D. would buy
2. If you more carefully, you would not have had so many accident.
A. drive B. drove C. had driven D. has driven
3. “Tom more races if the trained hard.” The man said.
A. would win B. wins C. would have won D. would be winning
4. If I spoke English, my job a lot easier.
A. was B. were C. will be D. would be
5. “If you feel like a chat, .” David said to me.
A. phone to me tonight B. will you phone me tonight
C. phoned me tonight D. phone me tonight
6. I will lend them some money if they me.
A. ask B. will ask C. asked D. had asked
7. If we had known who he was, we him to speak at our meeting.
A. would have invited B. have invited
C. will invite D. would invite
8. “If you too much junk food, you would be a lot fitter.” Mother said.
A. ate B. didn’t eat C. didn’t ate D. had eaten
9. If I enough money. I would buy a house.
A. had B. had had C. will have D. have
1. If that hat costs much, I a small one.
A. would have bought B. will buy
C. bought D. would buy
2. If you more carefully, you would not have had so many accident.
A. drive B. drove C. had driven D. has driven
3. “Tom more races if the trained hard.” The man said.
A. would win B. wins C. would have won D. would be winning
4. If I spoke English, my job a lot easier.
A. was B. were C. will be D. would be
5. “If you feel like a chat, .” David said to me.
A. phone to me tonight B. will you phone me tonight
C. phoned me tonight D. phone me tonight
6. I will lend them some money if they me.
A. ask B. will ask C. asked D. had asked
7. If we had known who he was, we him to speak at our meeting.
A. would have invited B. have invited
C. will invite D. would invite
8. “If you too much junk food, you would be a lot fitter.” Mother said.
A. ate B. didn’t eat C. didn’t ate D. had eaten
9. If I enough money. I would buy a house.
A. had B. had had C. will have D. have