Hỗn hợp A gồm Fe3O4, Fe, Al và Al2O3. Cho A tan trong dung dịch NaOH dư được hỗn hợp chất rắn A1, dung dịch B1 và khí C1. Cho khí C1 (dư) tác dụng với A nung nóng được hỗn hợp chất rắn A2. Chất rắn A­2 tác dụng với H2SO4 đặc nguội, được dung dịch B2. Cho B2 tác dụng với dung dịch BaCl2 được kết tủa B3. Xác định các chất và viết phương trình hoá học xảy ra.

Phân tích đa thức thành nhân tử. Giúp mình với.

Cho tam giác ABC vuông tại A BC =4 A) C=30°, tính AB,AC B) AD là phân giác của A . Tính BD,DC ?

Trộn 100 ml dung dịch H2SO4 0,5 M với 100 ml dung dịch NaOH 4 M, tìm nồng độ của các ion

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Choose the best one (A, B, C or D) to complete the sentence. 1. No one else in the class plays the guitar John. A. as well B. as far as C. so well as D. as soon as 2. The Brit School is the most famous arts school in Britain. A. performing B. performance C. perform D. performed 3. Jane is not her brother. A. more intelligent as B. intelligent as C. so intelligent as D. so intelligent that 4. Since the 1970s, the festival in Glastonbury has taken almost every year and has grown in size. A. part B. place C. note D. notice 5. He drives as his father does. A. careful as B. more carefully C. the most careful D. carefully as 6. Dong Ho paintings are made on paper with beautiful colors. A. traditional – nature B. tradition - natural C. tradition – nature D. traditional - natural 7. I’ll be there I can. A. sooner as B. no sooner as C. as soon as D. soonest as 8. My village is not it was ten years ago. A. the same as B. the same to C. same as D. the same 9. The villagers are they were years ago. There is no change at all. A. differently from B. not as friendly as C. as friend as D. as friendly as 10. Water puppetry in the 11th century in the villages of the Red River Delta of North Viet Nam. A. originated B. formed C. started D. began 11. The puppet shows present themes of Vietnamese villages. A. city B. urban C. village D. rural 12. No one in my class is beautiful her. A. as – as B. more - as C. as - than D. the - more 13. The group is for their albums and tours around the world. A. well-knows B. know-how C. well-prepared D. well-known 14. Going by train isn’t convenient as going by car. BÀI TẬP TIẾNG ANH LỚP 7 – Có đáp án 36 A. so B. as C. more D. A & B are correct. 15. The performances of puppetry show in the countryside and . A. everyday life - folk rock B. every day life - folk people C. everyday life - folk tales D. every day life - folk stories

II. Write the second sentence so that it has a similar meaning to the first one. 1. It takes us more than two hours to see the film “Avatar”. The film “Avatar” 2. She likes to hang out with friends on Saturday evening. She’s interested 3. She only allows her children to watch television at weekends. She only lets 4. Could you help me with this box? Would you 5. DIY skills aren’t as hard to learn as I think. DIY skills are _______________________________________________ 6. Who will take care of the garden while you are away? Who will look 7. How about going window-shopping this afternoon? Shall 8. What leisure activity do you like most? What’s

a^2>12 bc cmr a^2/2+b^2+c^2>ab+bc+ca

Chứng minh định lí: Nếu một đường thẳng cắt một trong hai đường thẳng song song thì nó cũng cắt đường kia.

mong mọi người giúp em làm bài 14 15 16 17 mọi người nhớ làm ra giấy hộ em nha xong vote cho 5 start và ctlhn