Cho a>b>c>d là các số nguyên dương thỏa mãn a^2+ac-c^2=b^2+bd-d^2. CMR: ab+cd là hợp số.

hì giúp với em hứ không đăng ik đăng lai nữa ạ

.Ở nhiều nơi trên thế giới, trẻ em làm việc trong các lĩnh vực khác nhau, phần lớn trong ngành nông nghiệp, nơi các em có thể phải tiếp xúc với hóa chất độc hại và các thiết bị không an toàn. Số khác là trẻ em lang thang bán rong, hoặc chạy việc vặt kiếm sống. Một số trẻ giúp việc tại các gia đình hoặc làm tại các nhà máy. Tất cả các em đều không có may mắn sống một tuổi thơ thật sự, một nền giáo dục đầy đủ hoặc có một cuộc sống tốt đẹp hơn.” a.Đoạn văn được viết theo cách trình bày nào sau đây: a. Song hành b. Diễn dịch c.Tổng phân hợp d. Quy nạp b.Vấn đề phản ánh trong đoạn văn trên là gì? c.Em có đề xuất giải pháp gì để góp phần bảo vệ sự sống còn và phát triển của trẻ em

Mình cần lời giải chi tiết(TIM LUÔN Ạ) Cho tam giác ABC(Ab<AC). Đường tròn tâm I nội tiếp tam giác ABC tiếp xúc với AB, BC lần lượt ở D, E. Gọi M, N theo thứ tự là trung điểm của AC và BC. Gọi K là giao điểm của MN và AI. Chứng minh rằng: a) 4 điểm I, E, K, C cùng thuộc 1 đường tròn b) 3 điểm D, E, K thẳng hàng Cảm ơn các cậu.

Làm thế nào để khử độ tinh khiết của hidro

EXAMPLE: I / wonder / why you / not / reply last letter. ANSWER: I was wondering why you had not replied to my last letter. 41. She / a bath / every morning. …………………………………………………………………….. 42. Now / she dances / beautifully / than / used to. …………………………………………………………………….. 43. How long / it / take / him / get / school / every day ? …………………………………………………………………….. 44. Last Wednesday / Bill / ring / office /nine o'clock. …………………………………………………………………….. 45. I / live / Ho Chi Minh city / ten years. …………………………………………………………………….. 46. People / come / all over the world/ visit / city/ Hiroshima. …………………………………………………………………….. 47. Billy / an old man that / has to live with his children. …………………………………………………………………….. 48. Oliver Twist / first published / 1838. …………………………………………………………………….. 49. It / too heavy / him / lift. …………………………………………………………………….. 50. I / able to / come / tomorrow. ……………………………………………………………………..

Giúp em cái nha, nhanh nhất có thể ý

Làm hết nhé không mình sẽ report II/ Choose the best answer by circling A, B, C or D: (1.0 pt) 1. My father ..................to the zoo last week. A. go B. will go C. went D. goes 2. If we cut down more forests, there..............more floods. A. are B. have been C. were D. will be 3.Sydney Opera House is in .............................. A. England B. Australia C. Singapore D. France 4. It is getting light. Shall I turn ............the light to save electricity. A. off B. up C. on D. in C/ READING (2,0pts) I. Choose A, B, C or D to complete the following passage: (1.0 pt) AIR QUALITY People need to breath. If they don’t breath, they (1)............. die. But how clean is the air people breath? If they breath dirty air, they will have breathing problems and (2)............. ill. Plants and animals need clean air, too. (3)............. of things in our lives create harmful gases and make the air dirty, like cars, motorbike and factories. Dirty air called (4).............. air. Air pollution can also makes our Earth warmer. The problem of air pollution started with the burning a lot of coal in homes and factories. 1- A. will B. is C. are D. won’t 2- A. become B. became C. becomes D. will become 3- A. Some B. Many C. Few D. A lot 4- A. pollute B. polluted C. pollution D. polluting II- Read the passage carefully then answer the questions below. (1.0 pt) My name is Dick. I always wish to have a motorhome in my life. My motorhome won’t need to be big, but it may have everything I need inside. There will be a sofa and a lovely table in the head of the car. This will be the place for my friends when they visit me. It is like a living room. The biggest part of my motorhome will be the kitchen. It’ll be in the middle of the car. There will be some model equipments in the kitchen such as dishwasher, fridge, oven, washing machine.... A small toilet and a shower will be in the kitchen, too. The last part will be my bedroom. It is also my entertainment place. There will be a small bed, a wireless TV, and a high- tech computer. It would be fantastic if I had my own motorhome. The best thing about having a motorhome is that I can drive it myself to everywhere which I am interested. 1- What kind of the house does the writer wish to have? .......................................................... ................................... .............................................. 2- How many parts are there in the house? .......................................................... ................................... .............................................. 3- Will this house be big? .......................................................... .................................................................................. 4- Is the kitchen the biggest part of the house? .......................................................... ................................... .............................................. D.WRITING (2pts) I/ Arrange the following sets of words to make meaningful sentences: (1.0 pt) 1. recycle / the environment / bottles and cans / we will help / If we / .................................................................................................................................. 2. read and write / you / Could / when you were 6 / ? ................................................................................................................................... 3. will be able to / In 2030, / robots / do many things / like humans /. .................................................................................................................................... 4. visited / We / in the countryside / our grandparents / last week. .................................................................................................... II/ You and your classmates want to make your school “green” place. Write down four rules for the class members to follow. (1,0pt) RULES FOR A “GREEN” SCHOOL 1...................................................................................................... 2...................................................................................................... 3...................................................................................................... 4......................................................................................................

IV. Choose the word (a, b, c, or d) that best fits each of the blank spaces. Hi. I’m back in the U. S. I was with Matilda on her concert tour of Africa. The best part was Eritrea. The Eritrean people were very friendly and (31)______. The streets weren’t (32)______, but the markets often were. The restaurants were great, but the service was often (33)______. Some hotels were modern and some weren’t, but even modern hotels weren’t air-conditioned. The weather was very hot and (34)______, but Matilda’s concerts were great, and my whole trip to Eritrea was a lot of (35)______. 31. A. kind B. lucky C. reserved D. quiet 32. A. crowd B. crowded C. crowds D. overcrowding 33. A. slow B. slowly C. quick D. quickly 34. A. cold B. cool C. humid D. wet 35. A. fun B. joke C. humor D. humorous V. Read the following passage and choose the best answers to each of the questions below. My husband and I had a problem about our holiday last year. I wanted to have a lazy seaside holiday because I was tired and needed to relax. I loved lying in the sun, drinking iced beer and reading a good book. But Robert liked busy, cultural holidays. He liked visiting museums and art galleries. He hated sunbathing because he always went red, not brown. The travel agent tried to help us and suggested Greece. I said I love to sail to a quiet island, but of course Robert said he’d like to stay in Athens. It was easy to decide what to do, we flew to Athens together, Robert stayed there and I traveled to the island of Kos! 36.What is the passage written about? A. a trip to Greece B. a lazy seaside holiday C. a busy cultural holiday D. a problem about the holiday 37. The author ________________. A. liked sunbathing B. was tired and needed to relax C. liked a busy cultural holiday D. a & b are correct 38. What does the word ‘island’ in line 5 mean? A. a piece of land with water all around it B. a place in a desert that has trees and water C. a high piece of land that is not as high as a mountain D. a big area of salty water 39. Robert wanted ________________. A. to stay in Athens B. sunbathing C. drinking iced beer D. lazy seaside holidays 40. Kos is ________________. A. a town in Athens B. a city in Greece C. an island D. a place which has many island