Giải giúp em với ạ

giải hộ mình gấp với ạ

Hợp chất A có công thức R₂X; trong đó R chiếm 58,974% về khối lượng . Trong hạt nhân của nguyên tử R có số hạt không mang điện nhiều hơn số hạt mang điện là 1 hạt. Trong hạt nhân nguyên tử X có số hạt mang điện bằng số hạt không mang điện. Tổng số proton trong phân tử A là 38. Tìm công thức phân tử của A.

The Hue Festival is a cultural event celebrated every two years in order to honour Hue Cultural Heritages as well as Viet Nam’s national identity. In 2000, this event got its official name “Hue Festival” as today. In this special event, a wide variety of traditional activities are held, such as kites playing, human chess… Performances of dances and fireworks are included. The festival aims at promoting several kinds of arts as well, with the participation of over 40 art companies from Viet Nam and foreign countries. From all over the world, thousands of artists gather in Hue and demonstrate their talents throughout the city.

A.Choose the best answer:

1.There are… activities at this event.

A.few                     B. some                      C. no                                   D. a lot of

2.This festival is held……………..

A.every year          B. every two years     C. once every three years   D. twice every year

B.Answer the questions:

What is the Hue Festival celebrated for?………………………………………………..

When did this event get its name as today?........…………………………………….….

Can art companies from foreign countries take part in this event?...............................................

Cân bằng phản ứng oxi hóa
1)      FeI₂+ H₂SO₄---->Fe₂(SO₄)₃ +SO₂+ I₂+ H₂O

2)      MnBr₂+Pb₃O₄+ HNO₃---->HMnO₄+ Br₂+ Pb(NO₃)₂ + H₂O

3)      CrI₃+ KOH+ Cl₂---->K₂CrO₄+ KIO₄+ KCl+ H₂O

4)      FeI₂+ H₂SO₄---->Fe₂(SO₄)₃+ SO₂+ I₂+ H₂O

5)      Cu₂S+HNO₃---->Cu(NO₃)₂+ CuSO₄+ NO₂+ H₂O

6)       FeSO₄+ KMnO₄+KHSO₄---->Fe₂(SO₄)₃+K₂SO₄+MnSO₄+H₂O

Giúp em gấp với ạ
1. You ________ play loud music at night. The neighbors will call the police. 

A. mustn’t         B. needn’t         C. might not         D. couldn’t

2. It’s late. I think we ………… better go.

A. had             B. have             C. should         D. would

3. Children ……………….. play on the grass.

A. needn’t               B. don’t have to        C. must            D. mustn’t

4. Don’t pretend you don’t know that you……. have a valid ticket on the bus.

A. have to        B. must        C. need        D. should

5. You .................take photographs here. It is a restricted area.

A. have to         B. mustn’t         C. don’t have to        D. shouldn’t

6. Everyone’s asleep. We …………………… make a noise

A. couldn’t         B. mustn’t         C. needn’t         D. wouldn’t

7. I’m quite happy to walk. You …………………. drive me home.

A. don’t         B. haven’t         C. mustn’t         D. needn’t

8. You _____ drink this. It is poison. 

A. must         B. needn't         C. mustn't         D. shouldn't

9. You aren’t allowed to take photographs here. 

A. You needn’t take photographs here.         B. You can’t take photographs here.

C. You don’t have to take photographs here.       D. You mustn’t take photographs here. 

10. She felt ill and _____ leave early.

A. has to         B. must         C. had to         D. ought 

11. You ___________ use your mobile phone in the examination room.    

A. oughtn’t to        B. mustn’t        C. don’t have to        D. shouldn’t

12. My grandparents live in the suburb, so whenever we visit them, we___________ a bus.

A. must take        B. should take        C. have to be taken        D. have to take

13. “Must I take my umbrella?” - “No, you ___. It’s not going to rain.”

 A. mustn’t            B. have to            C. needn’t                D. don’t

14. The Prince’s aircraft had to undergo a security check and so we ___ to him for almost an hour. Father was very impressed as normally he could have counted on nothing more than a handshake.

A. might talk          B. were able to talk              C. could have talked       D. may have talked

15. The book is optional. My professor said we could read it if we needed extra credit. But we ___ read it if we don't want to.

A. cannot          B. don't have to                       C. must not                   D. should not

16. He…………….his job because he seems very happy.    

A. would like        B. can like        C. will like        D. must like

17. “Must you come when your neighbour calls?” – “No, I…………………..

A. must not        B. mustn’t        C. don’t have to        D. must not come

18. You ……………… exercise regularly.

A. mustn’t        B. should        C. would        D. needn’t

19. Young people ______ obey their parents.

A. must                B. may                  C. will                 D. ought to

20. Laura, you and the kids just have dinner without waiting for me. I ______ work very hard today.

A. can                 B. may                  C. should              D. would

21. I ______ be delighted to show you round the factory.

A. ought to             B. would                C. might               D. can

22. Leave early so that you ______ miss the bus.

A. didn’t               B. won’t                 C. shouldn’t            D. mustn’t

23. Jenny's engagement ring is enormous! It ______ have cost a fortune

A. must               B. might                 C. will                 D. should

24. You ______ to write them today.

A. should              B. must                 C. had                D. ought

25. If you like, we ___ volleyball with the children while the men ___ up the barbecue.

A. could play - are setting        B. could have played - have set

C. will play - were setting        D. can play - had been setting

26. Unless he runs he______ catch the train.

A. will                 B. mustn’t               C. wouldn’t            D. won’t

27. The lamp ___ be broken. Maybe the light bulb just burned out.

A. could not             B. might not                  C. must not                   D. cannot

28. Do you always have to say the first thing that pops into your head. ___ you think once in a while before you speak?

A. Can not           B. Don't         C. Can't         D. Why

29. "______you hand me that pair of scissors, please?"

A. May                B. Will                C. Shall                D. Should
30. You ___ forget to pay the rent tomorrow. The landlord is very strict about paying on time.
A. couldn't       B. don't have to                       C. mustn't                     D. needn’t

Tìm y
a) 2y(y-1)-y(-4+2y)+4=0
b) (2y+3)(y+2)-(y-4)(2y-1)=18