9.Nêu pp hóa học tách các chất sau đây ra khỏi hh chất rắn S, K2SO4, Zn, BaSO4, CaSO3 10.Tách riêng từng chất nguyên chất từ hh : đá vôi, vôi sống, thạch cao và muối ăn.

cho 2 góc kề bù AOB và BOC trong đó góc AOB=1/2BOC . Vẽ tia phân giác OM của góc BOC , vẽ tia phân giác ON của góc MOC. Chứng minh ON vuông góc OB làm dùm mình vs nha mình cảm ơn tr

27x ² - 8y ³

Giups tui bài này nha nhanh giùm thời gian có hạn.

Tinh chế Cl2 có lẫn O2, CO2 và CO

Giúp mình với căn ( 3- căn 5 ) ( căn 10 - căn 2 ) ( 3 + căn 5)

Question 5. Rewrite the following sentences. 1.“ You should enroll in this college," said my father. My father advised ............ 2. if she doesn't hurry, she will miss the last train. Unless...... 3. Work hard or you pass the exam. → If........ 4. “Where are you working ,Nam?" Said Peter. Peter asked........ 5. Let's attend the Brighton Language center. → Why don't .............. 6. Practice speaking every day or you can't improve your English. → If............ 7. John lives in a small flat and he doesn't like it. → John wishes ......... 8. "Do your grandparents still live in Hue now? said Nam to me." → Nam asked ......... 9. Spending the weekend in the countryside is very wonderful. It's............. 10. Nga is pleased to meet her aunt again soon. → Nga is looking .............. 11. He worked hard to earn money. He could not pay his debt. → Although... 12. The traffic was heavy. I arrived on time. In spite of................. 13. The story was very sad. She was moved to tears. It was ........ 14. His family was so poor that she couldn't have much school. → His family was........... 15. People say he is the best-known writer. He is ....... 16. She loves children very much because she's the mother of a large family. → As a mother . 17. In spite of his age, Mr Benson runs seven miles before breakfast. → Though 18. It is a six-hour drive from London to Edinburgh. It takes ............ 19. I haven't enjoyed myself so much for years. → it's........... 20. It is said that he is one hundred years old. He is said ....

Giải phương trình bậc hai cos4x-2sin2x -1=0

Giải PT 2/x-3 + 3/x+3 = 3x+5/x ²-9 Chú thích: ( / ) phần

Bài 11: Cho 3 tập hợp : A = {1, 2, 3, 4} ; B = {2, 4, 6} ; C = {4, 6} a/ Tìm AnB, AnC, BnC b/ Tìm A U B , A U C ,B U C c/ Tìm A \B, A\C,C\B d/ Tìm An (B U C) và (An B) U (An C). Có nhận xét gì về hai tập hợp này ?