Cho biểu thức: A = (-a - b + c) – (-a – b – c) a) Rút gọn A b) Tính giá trị của A khi a = 1; b = -1; c = -2
Cho ba điểm A, B, C không thẳng hằng. Vẽ đường thẳng a cắt các đoạn thẳng AB, AC và không đi qua A, B,C. a, Gọi tên nửa mặt phẳng đối nhau bờ a, b, Đoạn thẳng BC có cắt đường thẳng a hay không? Vì sao? GIÚP TỚ VỚI NHÉ ĐAG CẦN GẤP
Trong các biển báo giao thông, biển nào sau đây có trục đổi xứng? ❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️
Công thức hóa học nào sau đây có phân tử khối lớn nhất? A: HNO2 . B: H2 O2 . C: CuO. D: ZnO.
Viết đoạn văn ngắn từ 10-12 câu tả cảnh bầu trời mùa đông sử dụng so sánh nhân hóa
20 câu làm đúng nha Sai nhiều báo cáo
113,75 :3,25 giúp mình giải với
help me I. Give the correct form of the words given to complete the sentences 1. The ________ of lakes, rivers, ocean or under water causes water pollution. CONTAMINATE 2. The street doesn’t look ______ because it has a lot of rubbish . ATTRACT 3. The music Club made so much noise that________ the complained to its owner. RESIDE 4. Are all types of pollution__________ humans and animals? HARM 5. The ____________are concerned about the oil spiIls in the East sea ENVIRONMENT 6. Dumping ______waste into the lakes and rivers has caused serious water pollution INDUSTRY 7. Many people in this area have cholera because they drink ____ water. TREAT 8. Examples of primary_____ are exhaust fumes from cars, soot from smoke and ash from volcanic eruption. POLLUTE 9. If we use water_____ , more people will have fresh water. CARE 10. The polluted water results in the_____ of many aquatic animals and plants DIE 11. Many fish in the lake near my house have died because of the _________water. POLLUTE 12. My friend and I are going to give a presentation about our _______problems. ENVIRONMENT 13. Too much use of _________lights in cities may cause light pollution. ELECTRICITY 14. Nowadays, people use too much herbicide so many animals don’t have enough food and they become ___________SICKNESS 15. Oil spills from ships in oceans and rivers make the _________ aquatic animals and plants. DEAD II. Choose the correct option A, B, C or D to complete the sentences. 1. …………water is one of the factors that have driven many species to the verge of extinction. A. Contaminating B. contaminate C. Contamination D. contaminated 2. It’s recommended that we become more concerned …………… the environment around us. A. of B. to C. with D. about 3. The ……………………use of pesticides and herbicides has led to contamination of groundwater in some areas. A. widespread B. occasional C. general D. experimental 4. Air ……………………, together with littering, is causing many problems in our cities today. A. pollute B. pollution C. polluting D. polluted 5. Many people in this city have received medical …………………… for the disease. A. support B. treatment C. help D. assistance 6. The reduction in air pollution was …………………… last year. A. drama B. dramatise C. dramatically D. dramatic 7. In many poor nations, there are frequent outbreaks of cholera and other diseases because people there untreated water. A. drink B. to drink C. drinking D. drank 8. The road in front of my office is always …………………… when it rains heavily. A. to flood B. flooding C. flood D. flooded 9. Too much carbon dioxide in the atmosphere causes global ………………… A. warm B. warming C. warmly D. warmth 10. It won’t be possible to save the Earth if we don’t take ……………………right now. A. action B. job C. work D. duty III. Fill each blank with a word/phrase in the box. substance light pollution Earth’s surface air pollution waste water temperature dumping surprised acid poisonous 1. If this factory continues ……………………poison into the lake, all the fish and other aquatic animals will die. 2. I think there is……………………around here because all trees and plants turn yellow and dry. 3. When thermal pollution happens, the……………………in rivers, lakes and oceans changes. 4. Soil pollution happens when people destroy the” … 5. Poison is a …………………… that can make people or animals ill or kill them if they eat or drink it. 6. They are all ……………………to see that all the fish they grow on their farm are dead. 7. You can see stars at night in the countryside because there isn’t any ……………………there. 8. Many households around the West Lake dump……………………into it so the water is polluted. 9. The vegetable price is increasing because the ……………………rain has caused damage to almost all vegetables in this area. 10. The……………………chemical waste in this factory is dumped into the river so its water now becomes almost black.
Cho 100 điểm, trong đó chỉ có 3 điểm thẳng hàng. Cứ qua 2 điểm ta vẽ được thẳng. Hỏi vẽ được tất cả bao nhiêu đường thẳng? (hai đường thẳng trùng nhau chỉ tính là một đường thẳng)
cho 2,06 muối Natri halogen A tác dụng với dd AGNO3 đủ thu được kết tủa B . kết tủa này sau khi pứ phân hủy hoàn toàn cho 2,16g bạc . muối A
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