e) $a^2+2b^2+2c^2 ≥2a(b-c)$
$⇔a^2+2b^2+2c^2 ≥2ab -2ac$
$⇔a^2+2b^2+2c^2 - 2ab+2bc ≥0$
$⇔2a^2+4b^2+4c^2-4ab+4bc ≥0$
$⇔(a^2-4ab+4b^2)+(a^2+4bc+4c^2) ≥0$
$⇔(a-2b)^2 + (a+2c)^2 ≥ 0 $ ( Luôn đúng )
Dấu "=" xảy ra $⇔a=2b=-2c $
I. Choose the word that has the underlined part pronounced differently from the others. 1. a. site b. city c. limestone d. find 2. a. airport b. offshore c. corn d. front II. Choose the suitable words or phrases to complete the sentences. 3. I can see a boy ___________a water buffalo. A. ride B. riding C. to ride D. rode 4. It's ___________to travel around Vietnam. A. interesting B. interseted C. interestingly D. interestedly 5. Would you mind ___________the windows? A. to close B. closing C. close D. closed 6. __________you mind if I smoke? A. Could B. Don't C. Do D. Would 7. Would you mind if I _____ the phone? a. use b. will use c. am going to use d. used 8._____ is a stream or river that falls from a height. a. Lake b. Waterfall c. Bay d. Island 9. ____ you mind finishing the work yourself? a. Will b. Do c. Can d. Should 10. We paddle the ____ slowly upstream. a. ship b. canoe c. bus d. train 11. I couldn't find a guide-book ____ in English. a. write b. writes c. writing d. written 12. Would you like me _____ now? a. go b. to go c. going d. to going 13. Britain ______oranges from Spain. a. imports b. exports c. sell d. has 14. _____ is hot liquid rock that comes out of a volcano. a. Limestone b. Marble c. Lava d. Ice 15. I would love____ them again. a. see b. to see c. seeing d. to seeing 16. _____ is a mountain with a hole in the top where fire, gas and lava sometimes come out. a. Volcano b. Valley c. Hill d. Mount 17. The Statue of _____, which has become a symbol of freedom, is situated in New York harbor. a. four American presidents b. Liberty c. Alcatraz d. Empire State 18. ____ is an area of land between hills or mountains. a. Valley b. Beach c. Bay d. Island 19. They have put a horrible statue right in the middle_____ their front yard. a. on b. in c. of d. to 20. Will you pick me _____ after the party? a. on b. over c. through d. up
Giúp mình với mấy bạn ơi mình cần gấp ạ hứa sẽ vote 5 sao và câu tl hay nhất👩💻🙇♀️🙇♀️
Nhanh tay lên giúp mik đi sẽ đc 5sao
Giúp mk làm bài hứa vote 5 sao. Hay nhất. Cảm ơn!
Viết 1 đoạn văn ngắn từ 5 đến 7 câu về chủ đề mồi trường có sử dụng câu rút gọn
Trong Word, lệnh Margins trong dải lệnh Page Lay outcó tác dụng gì? A. Chọn cỡ trang giấy B. Thay đổi kích thước văn bản C. Thiết lập lề văn bản D. Chọn hướng của trang giấy Câu 2. Để chọn hướng trang và lề trang cho văn bản em sử dụng nhóm lệnh nào? A. Home ->Paragraph B. Page Layout-> Page Setup C. Insert -> Text D. Home -> Clipboard
Cho tam giác ABC cóAB=AC. KẻAE là phân giác của gócBAC (E thuộcBE) . Chung minh rằng tam giácABF=tam giác ACE
Cho em hỏi cái này làm thế nào ạ Em cảm ơn
Cho (O), dây cung MN, tiếp tuyến Mx. Trên tia Mx lấy điểm T sao cho MT =MN. Đường thẳng TN cắt (O) ở S. Chứng minh: SMT = STM
IV. The passage below contains 10 mistakes in spelling, grammar and word form. UNDERLINE the mistakes and WRITE THEIR CORRECT FORMS in the space provided. Football has grown to become one of most successful sports and business opportunities on the planet. In the 2006 World Cup Finals, several hundred global companies advertised their production at stadiums in Germany. Through televising games the promotion of soft drinks, fast food, credit cards, and others items helped to generate a turnover of nearly $1 billion. This huge number of sponsorship has helped to raise the profile of businesses, but it is also valuable for football associations throughout the world. FIFA has made arrangements so that a lot of the money raised is returned to sport development programmes in the nations where competed in the tournament. Moreover, football and money don’t always result in happiness. Many problems are caused in the major competitions when teams demand more money for each performances. Often players become impatient, and demand to be paid before playing. This is unlikely to end well, cause lots of problems. If these arguments affect team spirit, then results are poor. Unfortunately, poor results mean that teams receive less money from the tournament organisers, so in the end the development of the game in these nations suffer. This means that the chance with improvement is small. Sometimes sport and money just don’t mix
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