Cho tam giác ABC có BD⊥AC, AB⊥CE, (D ∈ AC, E ∈ AB). Chứng minh AB − AC > BD − CE

Các câu hỏi liên quan

II. Write the correct form of the words given in capital letters write the answers in the box 1. Her birthday is on the……….…of September. (TWENTY) 2. There are five…….……in the kitchen. (KNIFE) 3. There are a lot of interesting…….……in the summer. (ACT) 4. He is a……….…person, so he sometimes has accidents. (CARE) 5. Don’t make a fire here. It’s very…….…… (DANGER) 6. They often play sports. They are very…….…… (SPORT) 7. Hoa’s sister goes.…….…..twice a week (SHOP) 8.My friend’s parents work at a secondary school. They are.….of English. (TEACH) 9. In my……….…, there is a market, a clinic, a post office and a supermarket. (NEIGHBOR) 10. Air…….……is a big problem in the big cities. (POLLUTE) III. Give the correct form of the verbs in brackets. Give your answers in the space provided. 1. Tuan and his brother (not watch)… …….…T.V at the moment. They (be) …….……asleep. 2. He usually (listen) ..…….…. to music and (watch). …….…..a newspaper in his free time. 3. I (not understand)… …….…this sentence. What this word (mean) …….…… 4. Their parents (travel). …….…..to Sapa next week. 5. (not, drive). …….…..your car too fast. It (be). …….…..dangerous. IV. Fill in the blanks with the correct prepositions 1. We always go……….…the city center…….……our own car. 2. I’d like to stay……….…home tonight. Is there anything interesting…….……T.V? 3. The Red River flows…..……..the Gulf of Tonkin. 4. John is often late…….……school but I’m always early. 5. Let’s listen…….……some music……….…the radio.