tính số mol và số nguyên tử của 6,4g đồng;14g khí nitơ;14,625 muối ăn NaCl

Cho góc xoy=120 độ. Ở phía ngoài của goc vẽ hai tia Oc và Od sao cho Oc vuông góc với Ox và Od vuông góc với Oy. Gọi Om và On lần lượt là tia phân giác của góc xOy và cOd. Vẽ tia Oy' sao cho Oc là tia phân giác của góc nOy'. a) Chứng minh rằng: Oy và Oy' là hai tia đối nhau b) Tính y'on c) Chứng minh rằng:Hai góc moy và noy' là hai góc đối đỉnh.

cộng phân thức sau: $\frac{y}{4x^2-2xy}$+$\frac{4x}{2y^2-4xy}$

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks. Over the last five years, more and more students from the school have taken part in environment projects, such as tree planting and improving the school grounds. But, no matter how we do, there’s always more that can be (25)_________ to improve the place where we live. This year students from the Conservation Club plan to work with local people to make a community garden near the school. As Tim, a student says: “No one (26) _______ to live in an unattractive area. If we work together, we can turn these areas into space that we can enjoy (27) ________time in.” This kind of local action is not just about (28) _________ environment. It also helps people to get to know (29)__________neighbors and it can help build stronger communities. If you care (30) ____________the state of your town, and you are interested in taking part in the project, please contact the school for further information. Question 25: A. done B. does C. do D. did Question 26: A. stay B. stays C. wants D. want Question 27: A. doing B. paying C. spending D. giving Question 28: A. 0 B. a C. the D. an Question 29: A. their B. his C. its D. her Question 30: A. about B. on C. at D. in

Đường tròn (C): x^2+y^2+4x-6y-12=0.viết phương trình đường tròn (C’) là ảnh của (C) qua phép tịnh tiến theo vectơ u (2;-3)

Với giá trị nào của a thì mỗi căn thức sau có nghĩa : a) Căn a/3 b) Căn -5a c) Căn 4-a d) Căn 3a+7

giúp em với, em đang cần gấp. chỉ cần lm bài 3.1 thôi ạ ( vì bài 3.2 ko có hình nên bỏ)hihi

Do you want some milk - ... I do not

Giúp mình vs huhu Mình sẽ cho 5 sao và cảm ơn

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. Ha Long Bay is a UNESCO world Heritage site in Quang Ninh province, in the northeast of Viet Nam. It has got over 1,600 islands and islets. Among the many ancient fishing villages in ha Long, only Cua Van floating village remains. All the houses and the buildings in the village float on huge wooden rafts. The villagers spend their days fishing and looking after the sea life. Then they sail to the mainland to trade their fish to things like food, drinking water and clothes. Most children go to floating schools and then spend the rest of their time learning important skills like swimming and fishing. They also help out their parents as much as they can. Their lifestyles may seem strange to many people, but it’s wonderful to live among such natural beauty and know you are protecting it. The villagers are able to help preserve their beautiful bay because they live directly on the water. Question 21: The word “they” in paragraph 2 is closest in meaning to _________. A. the builders B. the schools C. the villagers D. the houses Question 22: According to the passage, the villagers’ lifestyles may seem ________to many people. A. tiring B. strange C. dangerous D. boring Question 23: The villagers not only fish but also _________ the sea life. A. pollute B. damage C. look at D. look after Question 24: The villagers are able to help preserve their beauty bay because _______. A. they live on the land B. they live far from the sea C. they don’t live directly on the water D. they live directly on the water