Cho x, y, z thoả mãn x + y + z = 1. Chứng minh rằng (x + y)(y + z) + (y + z)(z + x) + (z + x)(x + y) = 1 + xy + yz + zx.

CHỈ CÁCH LÀM VỚI Ạ!NẾU ĐƯỢC HỨA SẼ THẢ 5 SAO VÀ TIM NHÉ!

47) tìm khoảng ĐB của các hs a) y= $\sqrt[]{x^{2}+4}$ b) y= $\sqrt[]{x^{2}-2x}$

Mong mn giúp mình, 1 câu thôi ạ

có thể gặp chùng roi ở đâu ? :>

Viết đoạn văn về ngôi nhà của mình gửi cho người thân hoặc bạn bè qua gmail (tiếng anh) Gợi ý ( dựa trên những gợi ý để làm thành một đoạn văn) - In the subject line, write briefly what the e-mail is about (To ......@gmail.com) - Begin the e-mail with a greeting (Dear/Hi/Hello....) - The parts of an e-mail: 3 parts 1/ Introduction: - Ask about her/his heath (How are you? Are you ok...?) - Thanks him/her for the previous e-mail or write the reason for e-mailing. (I'm glad/happy to get your email/letter...) (Thanks for your gift/doll.... on my birthday. It's beautiful/great) 2/Body: - Write the subjects (s) of the e-mail.... - write each subject in a new paragraph. (Now, I"ll tell you about my house. I live in....It's....It's surrounded by....There are....+..... But, I like....my bedroom....best because.....there is a picture of my family on the wall. (I like my bedroom best because it is lovely and I can study or relax everyday....) 3/ Conciusion: - Saying goodbye - Asking him/her to write back - Sending regards to her/his family. (What about your house? Please write and tell me about it...) (Best wishes to you/ your sineerely..) (I look forward to hearing from you soon.

Cho phương trình: x²-(2m+2)x+m²+4=0 Tìm m để phương trình có 2 nghiệm phân biệt sao cho nghiệm này gấp đôi nghiệm kia.

IV. Conditionals 1. “Would you mind if we …………… you by your first name?” “Not at all. Please call me Tom.” A. called B. call C. calling D. want to call 2. I wouldn’t go there at night if I ……….. you. A. am B. was C. were D. had been 3. If I ……………. get a pole, I’ll go fishing. A. can B. could C. may D. might 4. If you ………….. a choice, which country would you visit? A. have B. had C. have had D. will have 5. If you …………. to be chosen for the job, you’ll have to be experienced in the field. A. want B. wanted C. had wanted D. wants 6. If I had enough money, I ………… abroad to improve my English. A. will go B. would go C. should go D. should have to go

các bạn làm giúp tôi với 5 sao cám ơn và CTLHN

II. Choose the best answer a, b, c or d to complete the sentence. 1. I went on a trip to the countryside and had my first experience _______ farm work. a.on b. with c. for d. of 2. We usually spend our holiday in the village _______ our grandparents live. a.what b. where c. which d. when 3. I think country life is so boring and _______ because you’re not close to shops and services. a. unhealthy b.inconvenient c. comfortable d. peaceful 4. On the farm, uncle Duong showed us how to _______ cucumbers. a. plough b.produce c. pick d. put up 5. Mongolian children start to learn _______ before they can walk. a. horse riding b.riding horse c. ride horse d. horse ridden III. Underline the correct form of the word. 1. We’ve all been working very hard / hardly and now we’re tired 2. Our school Internet connection is really slow / slowly. 3. What’s the matter with him? He looks angry / angrily. 4. The children are playing quiet / quietly in the garden. 5. Rural areas are common / commonly known as the countryside or a village.