Người ta cần chế tạo một hợp kim có khối lượng riêng 5g/cm3 bằng cánh phá trộn đồng có khối lượng riêng 8900kg/m3 với nhôm có khối lượng riêng là 2700kg/m3 hỏi tỉ lệ giữa khối lượng đồng và khối lượng nhôm cần phải pha trộn

Khi phân huỷ hoàn toàn 47,4 gam KMnO₄ phản ứng xảy ra như sau:
2KMnO₄    →  K₂MnO₄ + MnO₂ + O₂
Thể tích khí oxygen thu được ở 25^oC và 1 bar là

2 đơn vị ,8 phần mười . Viết số thập phân

Phân tích tử và mẫu thành nhân tử rồi rút gọi
a, 2x²+2x
x+1

b, x² + x
x+1

c, x² - 1
x + 1

d, -3x² + 6x
3x - 6

Chỉ ra và nêu tác dụng của các từ ngữ thuộc phương Nam bộ trong bài thơ Nhớ Bắc của tác giả Huỳnh Văn Nghệ

A = 1.2² + 2.3² + 3.4² + .... + 98.99²

1. Have you ever taken a train to discover Britain’s ______________ countryside? (picture)
2. ______________ in the countryside north of Ha Noi still continue the tradition of water puppet shows.
(village)
3. The river flows ______________ in rural countryside between green fields. (quiet)
4. Raising animals was only secondary to other forms of ______________. (farm)
5. There’s nothing like the ______________ of the countryside, the quiet and the lack of distraction. (peaceful)
6. People living in rural areas are likely to have unique ______________ care needs. (support)
7. The ______________ of Viet Nam comes from every aspect of life through photos, texts, poems, etc.
(beautiful)
8. The ______________ stopped work, sat down and started to eat and drink. (harvest)
9. Some thought him ______________ because he disliked meeting people. (sociable)
10. The cost of ______________ is much higher in cities than in the country. (live)
1. Horses, mountain bikes and feet work _____________ on grasslands. (good/ well)
2. Agriculture is still based on _____________ methods in some countries. (traditional/ traditionally)
3. The _____________ populated provinces present a different economic picture. (dense/ densely)
4. He is very _____________ he often buys things for other people. (generous/ generously)
5. The village is _____________ situated in a quiet spot near the river. (beautiful/ beautifully)
6. Our house is very central, so we can _____________ get to theatres and cinemas. (easy/ easily)
7. They have replanted many areas with rare and _____________ plants. (unusual/ unusually)
8. She _____________ ran down the stairs to greet her cousins. (excited/ excitedly)
9. The Thompsons left their homeland and looked for a _____________ place to stay. (permanent/
permanently)
10. Some reporters spoke _____________ about rural development. (optimistic/ optimistically)
1. Average incomes in rural areas are rising _____________ those in the city. (slow)
2. The conditions they’re living in are _____________ we thought. (bad)
3. Your book looks _____________ mine. Can I borrow it for some days? (interesting)
4. The evening in the countryside is often _____________ that in the city. (peaceful)
5. Many families in the suburbs are _____________ the ones you meet in the urban. (happy)
6. With the help of technology we can live _____________ ever before. (convenient)
7. Watching football is one of Britain’s top leisure activities, even _____________ eating out. (popular)
8. Henderson said that he could run _____________ anybody else in the class. (fast)
9. This year’s harvest season seems to come a week _____________ usual. (early)
10. All these students are good, but some work _____________ others. (hard)
1. This year’s exam was much _____________ than last year’s.
A. the harder
B. harder
C. more hardly
D. more hard
2. The growth rate of rice farms is _____________ that of corn farms this year.
A. higher more than B. high more than
C. more higher than D. higher than
3. I think living in the city is _____________ living in the countryside.
A. more expensive than
B. expensive more than
C. as expensive more than
D. more than expensive
4. Our house in the town looks _____________ than their house in the country.
A. moderner
B. more moderner
C. more modern
D. modern
5. The development of cities happens _____________ than that of the countryside.
A. more rapidly
B. much rapidly
C. more rapid
D. more rapidly as
6. We could go back to the days when life was _____________ it is today.
A. slower than
B. slowlier than
C. slower
D. more slowly
7. I think you’ll find going fishing _____________ than playing mobile games.
A. more relaxing much
B. much more relaxing
C. more much relaxing
D. much relaxing more
8. My parents’ farm is very big, but my uncle’s is even _____________.
A. more bigger
B. more big
C. bigger than
D. bigger
9. Doing the shopping in the countryside is _____________ that in cities.
A. the least convenient
B. less conveniently than
C. less convenient than
D. least conveniently
10. Adding fertilizer to the soil will help the plants to grow _____________.
A. more quick
B. quicklier
C. more quickly
D. quickly more

8. If we don’t ______________ the grain soon, it will start rotting in the silos.
9. Do you want to know how to ______________ fruit trees in your own garden?
10. You can ______________ fish with a hook in a small pond near my house.
1. Do you like to have a farm tour and try your hand at milking ______________?
A. cows
B. fish
C. pigs
D. dogs
2. After harvesting rice, the farmers often ______________ it in the sunlight.
A. collect
B. water
C. dry
D. plant
3. The farmers were ______________ because they warmly welcomed us and accommodated our needs.
A. hospitable
B. healthy
C. interesting
D. well-trained
4. Ploughing the ______________ with buffalos is a common cultivation method in the highlands.
A. crops
B. lakes
C. ponds
D. fields
5. It was so fun when we came to the point of herding the ______________.
A. fruit
B. trees
C. cattle
D. poultry
6. This national park is a ______________ and tranquil place to go and visit.
A. crowded
B. peaceful
C. noisy
D. busy
7. As a main source of food, paddy rice is ______________ in about 123 countries.
A. picking
B. growing
C. loading
D. herding
8. The farm has a ______________ expanse of grassland for us to play football.
A. vast
B. short
C. limited
D. narrow
9. My cousin rode the bike ______________ through the narrow soil paths.
A. clearly
B. skillfully
C. exactly
D. hardly
10. They got about 30 million tons of grain at the end of the ______________ season.
A. planting
B. watering
C. ploughing
D. harvesting
1. There isn’t enough wind to _2. Our family ______________ the cabbage and turnips from our field.
3. Their fields ______________ about 5 km, or 3 miles, north to south.
4. I helped her ______________ to the cows, to feed the chickens, and to plant carrots.
5. It is important to ______________ rice grain as soon as possible after harvesting.
6. Her farm aims to grow enough barley to ______________ the pigs in all seasons.
7. The farmers ______________ their fertile fields with oxen in the traditional way.
8. If we don’t ______________ the grain soon, it will start rotting in the silos.
9. Do you want to know how to ______________ fruit trees in your own garden?
10. You can ______________ fish with a hook in a small pond near my house_____________ a kite, so let’s walk home.
1. Do you like to have a farm tour and try your hand at milking ______________?
A. cows
B. fish
C. pigs
D. dogs
2. After harvesting rice, the farmers often ______________ it in the sunlight.
A. collect
B. water
C. dry
D. plant
3. The farmers were ______________ because they warmly welcomed us and accommodated our needs.
A. hospitable
B. healthy
C. interesting
D. well-trained
4. Ploughing the ______________ with buffalos is a common cultivation method in the highlands.
A. crops
B. lakes
C. ponds
D. fields
5. It was so fun when we came to the point of herding the ______________.
A. fruit
B. trees
C. cattle
D. poultry
6. This national park is a ______________ and tranquil place to go and visit.
A. crowded
B. peaceful
C. noisy
D. busy
7. As a main source of food, paddy rice is ______________ in about 123 countries.
A. picking
B. growing
C. loading
D. herding
8. The farm has a ______________ expanse of grassland for us to play football.
A. vast
B. short
C. limited
D. narrow
9. My cousin rode the bike ______________ through the narrow soil paths.
A. clearly
B. skillfully
C. exactly
D. hardly
10. They got about 30 million tons of grain at the end of the ______________ season.
A. planting
B. watering
C. ploughing
D. harvesting

Một ôtô chuyển động thẳng chậm dần đều từ tốc độ 20 m/s thì sau khi đi được quãng đường 50 m thì dừng lại. Kể từ lúc hãm phanh, tính:
a) Độ lớn của gia tốc của ôtô
b) Thời gian ô tô dừng lại.
c) Tốc độ ô tô khi dịch chuyển được 25 m.
d) Thời gian để tốc độ ô tô còn một nửa tốc độ lúc bắt đầu hãm phanh.

$\left\{\begin{array}{l}\frac{\mathrm{y}+\mathrm{x}}{\mathrm{x}-2\mathrm{y}}=4\\ \frac{3\mathrm{x}+2\mathrm{y}}{\mathrm{x}-2\mathrm{y}}=11\end{array}\right.$

Cho tam giác ABC vuông tại A có góc B =60° , kẻ tia Ax song song BC . Trên tia Ax lấy điểm D sao cho AD=DC . Tứ giác ABCD là hình gì ? Vì sao?

CHỦ ĐỀ BẰNG CHỨNG BÀI THƠ : TIẾNG ĐẦN MƯA "Bích Khê"

Ý (1)Làm rõ chủ đề : Bằng Chứng :

Ý (2)Làm rõ chủ đề : Bằng Chứng :

Ý (3)Làm rõ chủ đề : Bằng Chứng :

Ý (4)Làm rõ chủ đề : Bằng Chứng :

khi dọn lều trại Giáo viên yêu cầu học sinh không được để chai thủy tinh hoặc Chai nhựa đựng nước trong rừng thì có thể đi thả hoại làm thế nào mà chảy nước có thể tạo ra được Ngọn Lửa

Một đội bóng đá thi đấu trong một sân vận động có sức chứa 55 000 khán giả. Với giá mỗi vé là 100 nghìn đồng, số khán giả trung bình là 27 000 người. Qua thăm dò dư luận, người ta thấy rằng mỗi khi giá vé giảm thêm 10 nghìn đồng, sẽ có thêm khoảng 3000 khán giả. Hỏi ban tổ chức nên đặt giá vé là bao nhiêu để doanh thu từ tiền bán vé là lớn nhất?

Khử mẫu của biểu thức $\frac{\sqrt{3}}{5\sqrt{5}}$

C) cos(x+10°)=55°
D) cos (2x+π/5)=-1

Scouting began in the United States in
A 1907
B1910
C1917
D1920

phân tích nghệ thuật sử dụng ngôn ngữ từ ngữ cấu trúc thơ biện pháp tu từ của bài thơ bạn đến chơi nhà

Giải hệ phương trình sau: (3-x)(4-x)=0

Cho hình bình hành ABCD. Gọi E, F lần lượt là trung điểm của các cạnh AB, CD. Chứng minh rằng:
a) Hai tứ giác AEFD, AECF là những hình bình hành;
b) EF = AD, AF = EC.

TOÁN 10: C/m rằng với mọi tam giác ABC, ta đều có:
a, $\frac{1}{HA}+\frac{1}{HB}+\frac{1}{HC}=\frac{1}{r}$
b, cotA + cotB + cotC = a² + b² + c²/ 4S
c, tanA / tanB = $\frac{c^2+a^2-b^2}{c^2+b^2-a^2}$ (với A;B khác 90°)
d, c² = (a - b)² + 4S. 1 - cosC/ sinC

nội dung nào sau đây phản ánh đúng điểm tương đồng của cuộc đấu tranh ngoại giao trong cuộc đấu tranh chống Pháp và Mỹ