( x - 3 ) ( x + 7 ) - ( x + 5 ) ( x - 1 )

Hãy tính số mol và khối lượng của : 

22,4 lít khí H₂ 

3,36 lít khí N₂

0,896 lít khí CO (các khí đo ở đktc)

Cộng các phân thức sau 

\(\dfrac{4}{x+2}+\dfrac{2}{x-2}+\dfrac{5x-6}{4-x^2}\) 

M=\(\dfrac{1}{x-1}-\dfrac{4}{x+1}+\dfrac{7x-1}{x^2-1}\)

a, Rút gọn M 

b, Tính giá trị của M tại x = -3

Choose the best answer.

1. Tet is an occasion for family_________ in Viet Nam.

A. visiting                              B. meeting                 C.reunions           D. seeing

2. Teenagers love ________ games and ________  friends.

A. play-text               B. to play-text           C. playing-texting                D. playing-to text

3. At the Mid-Autumn Festival, kids can sing, dance, and enjoy moon-cakes ; ____________, every child likes it very much.

A. However                           B. Moreover              C. Because                D. Therefore

4. I detest…………….so early in the morning.

A. get up                    B. getting up             C. gets up                  D. to get up

5. You should ____________ for information about a custom or tradition.

A. look                              B. looked                             C. looking                   D. looks

6. In the UK, there are lots of customs for table manners. For example, We ____________ use a knife and fork at dinner.

A. have to                     B. are having                   C. has to                          D. having to

7. In Viet Nam, you____________  use only the first name to  address people older than you.

A. should                        B. must                           C. shouldn’t                      D. have to

8. At the Mid-Autumn Festival ,kids can sing, dance, and enjoy moon-cakes ; ____________, every child likes it very much.

A. However            B. Moreover                            C. Because                        D. Therefore

9. She is famous __________ her intelligence. She designs many special styles for Ao dai.

A. in                                      B. for                                      C. with                                   D. into

10. We __________wear uniform at school from Monday to Saturday. That’s good way and equal to everyone.

A. have to                             B. haven’t to                        C. could                                 D. must

11.  Peter: Some ethnic groups have their own ways of life and customs. Daisy: ………. .

A.  How interesting! B.  I don’t like it.                  C.  I see                                  D.  Exactly.

Choose the word whose underlined part pronounced differently from the others:

1. A. customs            B. huge                       C. museum                D. community

2. A. sound                B. cloud                     C. found                     D. favourite

3. A. crafts                 B. comics                   C. streets                    D. stamps

Choose the word which has a different stress pattern from the others.

4. A. paddy                 B. worship                     C. heritage              D. unhealthy

5. A. grassland            B. preserve                   C. scenery             D. incense

Choose the word whose underlined part pronounced differently from the others:

1. A. customs            B. huge                       C. museum                D. community

2. A. sound                B. cloud                     C. found                     D. favourite

3. A. crafts                 B. comics                   C. streets                    D. stamps

Choose the word which has a different stress pattern from the others.

4. A. paddy                 B. worship                     C. heritage              D. unhealthy

5. A. grassland            B. preserve                   C. scenery             D. incense

Cho tam giác ABC vuông tại A, AC>AB, đường cao AH. Lấy điểm K nằm giữa H và C sao cho HK = AH. Từ A kẻ đường thẳng Ax // BC, từ K kẻ đường thẳng Ky // AH. Gọi E là giao điểm của Ax và Ky. Gọi P là giao điểm của AC và KE.( VẼ HÌNH GIÚP MÌNH NHA )

 a. Tứ giác AHKE là hình gì? Vì sao?                                     

 b. Chứng minh tam giác ABP vuông cân               

 c. Vẽ hình bình hành APQB. Gọi I là giao điểm của BP và AQ. Chứng minh tam giác AIK cân.

d. Chứng minh H, I, E thẳng hàng.