Trong phòng thì nghiệm, người ta điều chế khí oxit sắt từ Fe3O4 bằng cách dùng O2 oxi hóa sắt ở nhiệt độ cao. Để điều chế được 2,32g Fe3O4 cần dùng: a) Bao nhiêu gam sắt ? b) Bao nhiêu lít khí O2 ( ở đktc)

Tính gtln, gtnn a) A=4x-x^2+3 b) B=2x-x^2-7

6. Mr and Mrs Smith (travel) to Hanoi. 7. My sister doer her homework. She sleep 8. His parents don’t working in the factory. They do the gardening. 9. The girl does’t the housework. She (watch) TV. 10. Nga (read) a book now? 11. They (play) a game in the yard? 12. The children (wash) their clothes? 13. Your mother (travel) to Danang now? 14. What Mr Hung (read) now?He (listen) to the radio. 15. She (travel) to work by car? 1. My brother ( do ) ..............his homework in his room now . He ( do) ............. it every evening. 2. You can use my dictionary . I ( use ) ....... it every day but now I ( not / use ) ....................... it. 3. Mr Smith often ( teach ) .......... Class 6A, but this morning he ( teach ) ............... class 6B. 4. Trang usually ( listen ) ............. to the teacher in class , but she ( not / listen ) .............. now; she ( look ) ...................... out of the window . 5. There ( be ) ............................. many flowers in the garden. 6. Every day , Mr Hung ( not / drive ) ................. to work . He ( travel ) ........................ by taxi. 7. Nam ( go ) ..............to school on foot every day , but today he ( ride )................ to school . 8. I ( have ) ................literature on Monday. 9. My teacher ( live ) ....................in the city . 10. They ( play ) ....................soccer in the stadium at the moment . 11. My school ( be ) ...............small but beautiful. 12. Every day , Trang ( get ) ...........up at five o’clock . 13. Dung ( watch ) ...........television every evening. 14. I (not / be ) .............hungry and I ( not / want ) ............any rice.

Trong kinh tế có một số khái niệm : Thặng dư sản xuất, thặng dư tiêu dùng, hàm cầu, hàm cung, điểm hoà vốn. Hãy giải thích rõ các khái niệm trên. Dùng tích phân xác định để nêu cách tính thặng dư sản xuất, thặng dư tiêu dùng, điểm hoà vốn khi biết hàm cung, hàm cầu. Dùng đồ thị để minh hoạ

Câu 1: tìm x và y bt: [(x-2y). (x-7y) - x² + 4y²] ÷ (x-2y) = 18 Câu 2: Xác định hệ số a, b sao cho x^4 + ax³ + b chia hết cho x²-1.

Mn hướng dẫn cách vẽ tay anime cơ bản đi ạ, vẽ sao cho đẹp hơn ( or cách tỉa tóc ) Cả 2 càng tốt nha.

11. I’d like to go with you tonight but I am very busy.  _____________________________________________________________________________ 12. She wasn’t able to answer the questions, so she failed the exam.  _____________________________________________________________________________ 13. Peter was very nervous and failed the driving test.  _____________________________________________________________________________ 14. I can’t tell you what time it is because I don’t have a watch.  _____________________________________________________________________________ 15. She didn’t learn mathematics; that’s why she was cheated by that salesman.  _____________________________________________________________________________ 16. We missed the train because the clock wasn’t right.  _____________________________________________________________________________ 17. The dress is very expensive, so she can’t buy it.  _____________________________________________________________________________ 18. The teacher was very angry. His pupils did their homework carelessly.  _____________________________________________________________________________ 19. I never feel lonely because I have lots of good friends.  _____________________________________________________________________________ 20. We didn’t go on holiday because we didn’t have enough time.  _____________________________________________________________________________ 21. We got lost because we didn’t a map.  __________________________________________________

Bài 3: Chuyển mệnh đề IF trong các câu sau sang dạng đảo: 1. If I wake up late, I will be late for work. …………………………………………………………………………………………… 2. If my husband cooks, he burns the food. …………………………………………………………………………………………… 3. If Julie doesn't wear a hat, she will get sunstroke. …………………………………………………………………………………………… 4. If she doesn't eat well, she will tired. …………………………………………………………………………………………… 5. If you mix water and electricity, you get a shock. …………………………………………………………………………………………… 6. If people eat too many sweets, they get fat. …………………………………………………………………………………………… 7. If you smoke , you get yellow fingers. …………………………………………………………………………………………… 8. If children don’t play outside, they will get overweight ……………………………………………………………………………………………

Một thửa ruộng hình chữ nhật có chu vi là 640m, chiều rộng bằng 3/5 chiều dài. a/ Tính diện tích thửa ruộng đó. b/ Người ta để 1/6 diện tích vườn hoa để làm lối đi. Hỏi diện tích lối đi là bao nhiêu mét vuông ?

Ai bày mình cách sửa loiix màn hình video bị xanh với ạ. Vẫn có tiếng nhưng video ko có. mÀN HÌNH THÌ CHẲNG CÓ HƯ