tim x : 10 + 11 + 12 + 13 + ... + x = 5106

giải thích chi tiết giúp mik nha

Câu 6: (1 điểm) Trong mành đất hình chữ nhật có đo dài các cạnh là x (cm) và y (cm), người ta đào một cái giếng hình tròn có bán kính là r (cm). Tính diện tích S còn lại của mảnh đất theo x, y và r. Diện tích S có phải là một đa thức không? (biết hình tròn có bán kinh R thì diện tích S= πR²) GIúp mik câu này vs mọi người

Cho đa thức P = -4x² + 7xy – 3y² + 1 và Q = 5x2 – 7xy+ 4y² -1 al Tính P + Q b/ Chứng minh rằng không có giá trị nào của x, y để 2 đa thức có cùng giá trị âm helpppppppppppppppppppppp em cần gấp lắm luôn ạ

Hôdydotdysotsodoyddyey9xhcmhc hb nfhx

III. Complete the text with the correct form of the verbs in the list. This is my favourite singer. He (1) a famous rock star. He (2) in America. He (3) all around the world and (4) in rock concerts. He (5) his songs and(6) his own video dips. In his free time, he (7) staying at home listening to his CDs. At weekends, he usually (8) to expensive restaurants with his friends. He also (9) a lot of books about strange things. I can’t wait to see him perform live. I (10) him so much. D II. There is one mistake in each sentence. Underline and correct the mistake. Sentences Correction 1. Nam is my classmates. He watches TV every night. 2. I think collecting stamps are interesting. 3. My dad cooks very good. He loves preparing meals for our family. 4. I enjoy to ride my bike to school. 5. We usually go in a small lake out of the city at weekends. 6. Do you still play football next year? 7. We like doing fishing because it is relaxing. 8. Do you think bird-watching interesting? 9. I think playing volleyball interest because it is a team game 10. In my opinion, more people played monopoly in the future. ___________ ___________ ___________ ___________ ___________ ___________ ___________ ___________ ___________ ___________ ❻. READING I. Read the text and choose the correct answer. If you enjoy cycling for pleasure, doing it in London can be a shock. There are not enough lanes especially for bikes, and making your way through the traffic can be very risky. But if you have great passion, cycling in London can be exciting, and it is an inexpensive way of keeping fit if you live there. Some cyclists don’t mind spending a lot of money on expensive bikes. However, if you just want a basic bike that is only for occasional use, there are many cheap choices. Several markets have cheap bikes on sale which may not be impressive to look at but should be satisfactory. You should buy a cycling helmet if you want to cycle in London. Wearing a cycling helmet is not compulsory in Britain, but it is a good idea to wear one for protection. 1. What is the main idea of the passage? A. Cycling helmets B. Cheap bicycles C. Bicycle markets D. Cycling in London 2. According to the passage, cycling in London is A. easy B. difficult C. tiring D. boring 3. The word “it” in line 3 refers to A. cycling B. passion C. excitement D. doing exercise 4. The difficulty of cycling in London is described in lines A. 2 B. 5 C. 5-6 D. 8-9 5. According to the passage, all the followings are true EXCEPT that A. It is compulsory to wear a helmet when cycling in Britain. B. Some bikes in London are cheap. C. There are not many lanes especially for bikes. D. Some cyclists don’t want to buy expensive bikes.

Hiện nay tình hình dịch COVID diễn ra phức tạp. Ban Chỉ Huy Liên Đội mua 1m khổ 80cm loại 3 Zem( tấm mica). BCHLĐ mua về làm kính chống dịch có kích thước : chiều dài 17cm, rộng 22cm. Hỏi 1m khổ 80cm loại 3 zem có thể làm được bao nhiêu cái kính chông dịch?

hãy viết một đoạn văn trình bày suy nghĩ của em về nhận định "Bản thân cần chấp nhận sự thất bại như thế nào để thành công trong cuộc sống

Bài 1:cho ΔABC Vuông ở C ,có góc B=60 độ , tia phân giác của góc BAC cắt BC ở E,kẻ vuông góc với AB .(K thuộc AB ) ,kẻ BD vuông góc với AE (D thuộc AE) Chứng minh rằng :a)AK=KB b)AD =BC bài 2 :cho ΔABC cân tại A và hai đường trung tuyến BM,CN cắt nhau tại K a)chứng minh ΔBNC=ΔCMB b)chứng minh ΔBKC cân tại K c)chứng minh BC < 4.KM bài 3 :cho ΔABC vuông tại A có BD là phân giác ,Kẻ DE vuông góc BC (E thuộc BC).Gọi F là giao điểm của AB và DE Chứng minh rằng: a)BD là trung trực của AE (BD vuông góc với AE) b)DF=DC c)AD<DC d)AE // FC *Làm và vẽ hình hộ mình với các bạn ơi.Mình đang rất vội (CẢM ƠN CÁC BẠN RẤT NHIỀU)*

VII. Choose the word or phrase (A, B, c or D) that best fits the blank space in the following passage? Long ago a lot of people (41) ........ the moon was a god. Other people thought it was just a light in the sky. And others thought it was a big (42) ........ of cheese! The telescopes were made, and men saw that the moon was really another world. They wondered (43) ........ it was like. They dreamed of going there. On July 20, 1969, that dream came (44) ........ . Two American astronauts landed on the moon. (45) ........ names were Neil Armstrong and Edwin Aldrin.The first thing the men found was that the moon is covered (46) ........ dust. The dust is so thick that the men left (47) ........ where they walked. Those were the first marks a living thing had ever made on the moon. And they could (48) ........ there for years and years. There is no wind or rain to wipe them off. The two men (49) ........ rocks to bring back to Earth for study. They dug up dirt to bring back. They set up machines to find out things people wanted to know. Then they were off on their long trip (50) ........ the earth. 41a. thought b. guessed c. told d. said 42a. form b. stone c. ball d. round 43a. how b. which c. that d. what 44a. real b. true c. unreal d. untrue 45a. Their b. His c. Its d. Theirs 46a. by b. for c. to d. with 47a. fingerprints b. footprints c. handprints d. prints 48a. go b. remain c. put d. run 49a. got up b. gave up c. picked up d. set up 50a. back to b. from to c. into d. onto