Đáp án:
Giải thích các bước giải:
a) Xét ΔOBA có Oy là đường trung trực đồng thời là trung tuyến
⇒ ΔOBA cân tại O
⇒ OB = OA (1)
Chứng minh tương tự có : ΔOAC cân tại O
⇒ OC = OA (2)
Từ (1) và (2) ⇒ OB = OC
Ex1. Choose a word which has the underlined part pronounced differently from the rest 1. A. leave B. break C. repeat D. peaceful 2. A. photo B. going C. brother D. home 3. A. writes B. makes C. takes D. drives 4. A. guest B. gathering C. generous D. great Ex2. Choose the best replies for the questions: ( 1 point) A B Your answer 1. How is your first week at school? 2. Where is the cat? 3. Would you like to have a picnic? 4. What shall we do this afteroon 5. Can you tell me the way to the beach? a. Yes, I’d love to. b. Oh, wonderful. c. It’s under the table. d. Yes, First go straight. Then turn right. e.Let’s go out and have an ice-cream. 1. ………… 2. ………… 3. …………. 4. ………… 5. ………… Ex 3 Read the email and answer the following question.: ( 1,0 point) Dear Phong, I’m sorry I couldn’t write to you early because I was very busy. Now, we’re staying in a small hotel near a shopping area in District 10. Near my house, there is a cinema, a post office, a supermarket and some cafes. There are some big shops at the end of the street. It is also very noisy here because there’s always a lot of traffic day and night. In my hometown, I live in a quiet street, there are some small shops, a school and a post office in my neighbourhood but there isn’t a park and a cinema. The streets are narrow but they are cleaner and there isn’t so much traffic. The air is much fresher, too. And every house has a backyard and a frontyard. Love, Nam. 1. Why is it very noisy around his hotel? ............................................................................. 2. What are the streets in his neighbourhood like? ……………………………………….. 3. Is there a park in his neighbourhood? ............................................................................... 4.What are the houses in his neighbourhood like? ............................................................... Ex4. Put the verbs in brackets in the correct tense form 1.School(finish)---------------- at 4.30 pm every day. 2.------------you often (eat) -------lunch in the school canteen? 3.Listen! -------------they (sing) ---- in the classroom? 4.My family kike (spend)…………. our summer holidays at the seaside. 5.She (have) ------------- long black hair. 6.My father (be)------------- very kind. 7.I (go)------------ to the cinema with my sister this evening. 8.What ---------- your brother (do)-----------now? He (practice)-------- speaking English. Ex5. Write sentences, using the comparative or superlative forms of the adjectives 1. Mai/intelligent/Kien 2. My brother/strong/my sister. 3. Life in the city /exciting/ life in the countryside. 4. Doing our homework/important/ reading a novel. 5. Ho Chi Minh City/big/Ha Noi capital. 6. Mount Everest/the/high/the world. 7. Ba Be Lake/the/large/in Viet Nam. 8. Mekong River/the/long/ in Viet Nam. 9. Uluru / the/ beautiful/mountain/ Australia 10.Lan/the/good/English/my class.
Vì sao gọi Đàng Trong là chính quyền còn Đàng Ngoài lại gọi là nhà nước phong kiến vậy ạ?
Trình bày cuộc khởi nghĩa Yên thế (thời gian ,lãnh đạo, căn cứ tóm tắt diễn biến ,ý nghĩa )cho biết cuộc khởi nghĩa này có những đặc điểm gì khác so với các cuộc khởi nghĩa khác
giúp mình với mình cảm ơn trước
1. I ........................ born on the first of May. A. were B. was C. are D. is 2. The enemy ........................ by night. A. attack B. attacks C. attacked D. did attack 3. Mind about what I just ........................ now. A. said B. say C. did say D. didn’t say 4. Did you ever ........................ of such a thing? A. hear B. hears C. heard D. heart 5. He ........................ some eggs to make cakes. A. buys B. buy C. buied D. bought 6. There ........any eggs in the packet when I ....kitchen. A. was/ come B. were/ come C. was/ came D. were/ came 7. I ........................ a English course to improve all the skills. A. not joined B. joined C. did joined D. join 8. We ........................ to our friend last night. A. spoke B. speak C. speaked D. spoken 9. We ....... and ....... lunch at the cafeteria with them. A. talked/have B. talked/ had C. talk/had D. talked/ have 10. ........................ you attend yoga class when I ........................ at home? A. Did/ stayed B. Didn’t/ didn’t stayed C. Did/ didn’t stayed D. Did/ stayed 11. I ........................ his car to work while he was sleeping. A. drive B. drove C. driving D. driven 12. The man ........................ the door and ........................ pieces of paper. A. open/ thrown B. opened/ threw C. opened/ thrown D. open/ throw 13. He ........................ them into a room. A. led B. lead C. leaded D. leads 14. He ........................ off his hat and ........................ into the room. A. take/went B. take/go C.taken/go D. took/ went 15. The meeting ........................ 5 minutes ago. A. finished B. finish C.did not finish D. did finish Complete the sentences with the correct form of do or play. 1. Do you often _______ exercises? 2. My Dad ________ football for the town team when he was young. 3. My sister enjoys _______ table tennis in her free time. 4. My brother ________ basketball for the school team. 5. We _________ gymnastics at school yesterday. 6. I like _______ tennis. 7. My friend_________ judo twice a week. 8. My mother ____ yoga at the new sports centre. Complete the following sentences with the correct form of the verbs in brackets. 1. I (not be) very happy yesterday. 2. The people in the café (not be) friendly when I was there yesterday. 3. I (leave) my school bag at school this morning. 4. It (be) a great film in 2001. 5. Our teacher (tell) us to be quiet yesterday. 6. I went to the shop but I (not have) any money. 7. Susan (not know) about the exam and she did very badly. 8. I (buy) a ticket for the football match yesterday. Write the questions for the underlined words or phrases. 1. Minh brushes his teeth twice a day. → _____________________________ 2. Simon is in a lot of pain now because he has a toothache. → _____________________________ 3. I felt sick after eating that food. → _____________________________ 4. Nga went to see the dentist last week. → _____________________________ 5. Dr Lai will check your teeth. → _____________________________ 6. It took Dr Phong 10 minutes to fill Van’s tooth. → _____________________________ 7. My brother is going to the hospital. → _____________________________ 8. Mr. Cuong did morning exercises at 5.30 yesterday. → _____________________________ 9. Hoa received her aunt’s letter five days ago. → _____________________________ 10. There are twelve students in Lien’s class having toothache. → Give the correct form of the verbs in the past tense. 1. do ________ 2. teach _________3. send _________ 4. spend 5. begin _________ 12. have _________13. take _________14. go _________15. make ________ 11. buy______6. cut _________ 16. think________ 7. put _________17. see _________ 8. give _________18. eat _________ 9. write _________ 19. sing _________ 10. be _________20. wear ________
Mấy bạn từ hình mẫu dưới đây vẽ hình lên cho ngầu ngầu tí nhé thank you
Cho A = 5 + 5^2 + 5^3 + .... + 5^2019 . Chứng tỏ 4A + 5 là số chính phương
Một học sinh muốn nâng một thùng gỗ có khối lượng 30 kg từ mặt đất lên độ cao 1m A)Nếu dùng tay trực tiếp nâng vật thì học sinh đó dùng một lực tối thiểu là bao nhiêu ? B) nếu dùng một tấm ván để làm mặt phẳng nghiêng cao1m,dài 2m thì học sinh đó đó cần một lực nhỏ nhất bằng bao nhiêu? ( bỏ qua ma sát giữa vật và mặt phẳng nghiêng) C) nếu học sinh này chỉ dùng một lựccos độ lớn bằng ½ Độ lớn của lực ở câu b thì có thể dùng tấm ván dài bao nhiêu mét ?( bỏ qua ma sát giữa vật và mặt phẳng nghiêng )
Đặt 3 câu thì hiện tại hoàn thành
x^2+x+y-y^2= giải hộ em với ạ em cản ơn
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