Thực hiện phép tính

a.(2/căn3-1 + 3/căn3-2 + 15/3-căn3) x 1/căn3+5

b.(căn14-căn7/1-căn2 + căn15-căn5/1-căn3) : 1/căn7-căn5

Thực hiện phép tính

a. 5+2 căn5/căn5+căn2

b.Căn(2-căn3/2+căn3)

c.(2/căn3-1 + 3/căn3-2 + 15/3-căn3) x 1/căn3+5

d.(căn14-căn7/1-căn2 + căn15-căn5/1-căn3) : 1/căn7-căn5

Tóm tắt bài: Tôi đi học

Cho tam giác ABC, vẽ đường cao AH, (H ∈ BC). Cho biết ABC = 45◦, BH=20cm, HC =21 cm. Tính AC

Cho tam giác ABC có AB = 18; BC = 24 và BAC = 60◦.Tính độ dài cạnh AC

$$\begin{gathered} cho △ABC :\widehat{A }={90}^o,AC=24cm, AC=32cm \\ đường trung trực của BC cắt AC,BC tại D và E. Tính DE \end{gathered}$$

Exercise 4: Add a correct tag to each sentence 
1. Everybody will be there,  _____ ?

2. You'd rather not tell me, ________  ?

3. He'd better try harder,  ________ ?

4. There’s nothing on TV tonight,   _______  ?

5. You must give up smoking,  ______ ?

6. I didn't do anything wrong,  ____ ?

7. No one can help you, ________  ?

8. She must be tired now, _________  ?

9. Get out of my sight,  _________?

10. It seldom barks,  ______?

11. There are many girls here, ___________?  

12. I think they failed to reach the top, ________  ?

13. The men never killed children, _________  ?

14. Wash the dishes,   __________?

15. The actress must have taken that role, _________  ?

16. Let's drink wine,   ________?

17. Everyone was disappointed,  ________ ?

18. Your aunt must be happy with the gift,  _________ ?

19. That wasn't my fault,   ____________?

20. My uncle hardly gets up late,  ___________ ?

21. The islands must be very beautiful,   _________?

22. I am cowardly,________   ?

23.  No one likes the girl,___________   ?

24. Nothing wrong has happened,  _________ ?

25. I'm not supreme of all reality,  ________ ?

Exercise 5: Give the correct form of the verbs in brackets.

1. I (do) my homework when my mother (send) me to the chemist's with the prescription the doctor (give) her.

2. He (do) the experiment when the light (go) out.

3. At this time next week, we (live) in USA.

4. He (work) on the report at this time tomorrow.

5. When I (look) at my suitcase, I could see that somebody (try) to open it.

6. We (be) a few minutes late, so the film (start) when we (get) to the cinema.

7. I think she is the nicest person I (meet).

8. He (come) into the room after he (stand) outside for a moment.

9. After the telephone (buzz) for a minute, the doctor (answer) it.

10. He (have) a bad fall while he (repair) the roof.

11. Yesterday, when I (see) Tom, he (sit) in a corner with a book.  

12. James (weed) while Alex (cut) the grass in the garden this time yesterday.

13. Susan (wait) for you at 9 o'clock tomorrow.

14. This is the first time we (see) the Statue of Liberty.

15. By the time Anne graduated from high school, she (attend) seven different schools because her parents moved frequently.

$$\begin{gathered} giải △ABC:\widehat{A }={90}^o. Biết: \\ a) b=21cm, c=18cm \\ b) \widehat{B }={50}^o, a=12cm \\ c) b=9 cm, c=12cm \end{gathered}$$

x-3 + 6x2 + 9x

Bài 1:Cho tứ giác ABCD có AB//CD, AB//BC

a) Chứng minh AB=CD và AB=BC

b) Chứng minh góc A =  góc C, góc B=góc D

Bài 2: Cho tứ giác ABCD có AB=CD, AB=BC. Chứng minh AB//CD, AB//BC

Exercise 3: Find and correct the mistake in each sentence.

1. This is the most beautiful place I ever visit.

2. This time next week they will sit in the train on their way to Paris.

3. I came late to class. When I entered, the teacher writing something on the blackboard.

4. They will have English from nine to ten in this room. Don't annoy them then.

5. I made cakes. That's why my hands are covered with flour.

6. It is raining hard. We can't do anything until it stopped.

7. She had got into her shoes, put on her coat and went to the door.

8. What tune had they played when we came in?

9. That evening we stayed up to talk about the town, where he has lived for a long time.

10. I haven't seen her since we leaved school.

11. Coming into his room, he found that someone broke into it.

12. It always rains when they had just cleaned the windows.

13. The last time I saw him, he wore a black suit.

14. This is the talking between two friends who had just met up each other.

Exercise 4: Give the correct form of the verbs in brackets.

1. Last night, we (watch) television when the power (fail).

2. When we came in, they (prepare) the meal for us.

3. There (be) many changes in our village in the past few years.

4. Think carefully. I'm sure you (remember) his name.

5. After ancient Greek athletes had won a race in the Olympics, they (receive) a simple crown of olive leaves.

6. They (build) that bridge when I (be) there last year, they (not finish) it yet.

7. I (search) everywhere for the pen I (lose) yesterday.

8. "What you (do) at the moment, Ann?" "I (pack). I (catch) a plane to London tomorrow morning."

9. Since I left Venezuela six years ago, I (return) to visit friends and family several times.

10. When my parents (arrive) for a visit tomorrow, they will see our baby for the first time.

11. Don't worry. I (finish) the report before 10 o'clock.

12. I'll return Bob's pen to him next time I (see) him.

13. "I (go) out to buy a morning newspaper." "But it (rain) now. Why don't you wait until the rain (stop)?"

14. Hurry up or you (be) late for class.

15. He (be) to the theater three times this month.

Exercise 2: Chọn phương án đúng

1. I   _____your brother at Green Street yesterday afternoon.

A. meet B. met C. have met D. had met

2. He  _____ a cigarette and   to the window.

A. light; walked B. lit; walks C. lighted; walked D. lights; walk

3. After she  ______ for help, she   off her shoes and   in to save him.

A. shouted; took; jumped B. had shouted; took; jumped

C. had shouted; had taken; jumped D. shouted; had taken; jumped

4. I can't go with you because I  ________ my homework yet.

A. haven't finished B. had finished C. finished D. finish

5. He   _______for London 2 years ago and since then I   him.

A. have left; didn't see B. left; haven't seen

C. eft; hadn't seen D. had left; have't seen

6. The performance  at 7 o'clock and _______ for 3 hours. We all ______ it very much.

A. had started; had lasted; enjoyed B. had started; lasted; enjoyed

C. started; had lasted; enjoyed D. started; lasted; enjoyed

7. Tell them to stop and take a rest. They long enough.

A. have worked B. had worked C. have been working D. had been working

8. "You   ___________here before?” - "Yes, I   ________my holidays here last year.”

A. have you been; spended B. have you been; spent

C. had you been; spent D. were you; spent

9. "Your face is dirty, Tom.” - "All right, I ___  it.”

A. am washing B. am going to wash C. will wash D. will have washed

10. I _________  from him since he  two years ago.

A. hadn't heard; disappeared B. haven't heard; disappeared

C. didn't hear; has disappeared D. will not hear; disappears

11. After the guests  ____ , she  ____back into the living-room and __  off the light.

A. left; went; turned B. had left; had gone; turned

C. have leftt; will got; turned D. had left; went; turned

12. "You have just missed the last train.” - "Never mind. I_________  ”

A. will be walking B. am going to walk C. will walk D. am walking

13. "I  _______ the way to the Globe Theater.” - "OK. I _____  you.”

A. don't know; will show B. won't know; will show

C. don't know; am showing D. don't know; am going to show

14. Come in, please. I  _____ for you long.

A. have waited B. have been waiting

C. had been waiting D. have been waited

15. Who you  _______ to the cinema with last night?

A. went B. did you go C. had gone D. did you went

16. Detective: I'm afraid I must ask both of you. What __ at 10.20 p.m yesterday?  

Mr. X: I  ______ chess with my wife.

Mr. Y: I ________  to a play on the radio.

A. were you doing; am playing; was listening B. did you do; played; listened

C. were you doing; am playing; am listening D. were you doing; was playing; was listening

17. You  ______ my sister for a long time. _______  come to see us tonight?

A. haven’t seen; Will you B. won't see; Will you

C. hadn't seen; Would you D. haven’t seen; Are you going

Exercise 3: Add a correct tag to each sentence 
1. Hoa never comes to school late,  _________ ?

2. He hardly ever makes a mistake,  _________ ?

3. Nobody liked the play, _________  ?

4. She'd saved money when she bought it,   ___________?

5. They think he's funny, __________  ?

6. He ought to have made a note of it,   _____________?

7. She must be here,  _____________ ?

8. I remember you said she would come the next day,   ________________?

9. I don' think he will come,  ___________ ?

10. One can leave it,   _____________?

11. What a beautiful house,  _____________ ?

12. What handsome boys,  _______ ?

13. How lovely the baby is,   ____________?

14. How interesting the games are,  ____________ ?

15. People think she tell lie, ______________  ?

16. It seems that you are right, ____________  ?

17. What you have said is wrong,   _________?

18. Why he killed himself seems a secret,  _____________ ?

19. I wish to study English,  _____________ ?

20. One can be one's master,  __________ ?

21. What a long river, ____________  ?

22. How intelligent you are,   _________?

23. Nobody has arrived yet, _______  ?

24. Everybody looked so miserable,  _______ ?

25. Nobody's got to leave early,   __________?

Exercise 2: Add a correct tag to each sentence 
1. I'm late,_________ ?  

2. Let's have a party, _______?

3. Don't smoke, ________  ?  

4. He'll never know, ________  ?

5. I think he's from India, _________  ?

6. They must have stayed up late last night,  _________ ?

7. Let's go out, _________?  

8. That is your umbrella, _________?  

9. Those aren't Fred's books, ________  ?

10. Something is wrong with Jane today, _________  ?

11. Everyone can learn how to swim, _________ ?

12. Nobody cheated in the exam,_________ ?  

13. Nothing went wrong while I was gone, __________?  

14. I am invited to your party, _____________  ?

15. He'd better come to see me,  _________ ?

16. He seldom visits you,  _________ ?

17. You’ve never been in Italy,  __________ ?

18. No one died in the accident,   _________?

19. Going swimming in the summer is never boring,   __________?

20. What nice gifts,  _____ ?

21. Don't talk in class,  __________ ?

22. Sit down,  ________?

23. Nobody called the phone,  ________ ?

24. Everything is okay,  _________ ?

You have to leave early, _________  ?

Exercise 1: Add a correct tag to each sentence

1. Let's go shopping at Saigon Coop Mart, ________?

2. Children should drink a lot of milk and fruit juice, _____?

3. Bring your camera with you to the party,____   ?  

4. Remember to buy your mother some sugar on your way home, _____  ?

5. You think Internet is a means of education,  ________ ?

6. You ought go now, _____ ?

7. I think she won't come to your party,_____?

8. What a nice dress,______  ?

9. I think it is going to rain, ______  ?

10. He said that his father was a doctor,  _______ ?

11. Everything is all right,  ________ ?

12. She met nobody at the party,  _______ ?

13. Don't forget to turn off the lights before going out,  ________ ?

14. Be careful with that man,  ________ ?

15. Someone had come to our room,  _________ ?

16. She likes nobody to help her,   _______?

17. Everybody realized the danger,   _______?

18. Nobody complained, ______  ?

19. Mary hardly ever cooks,   _______?

20. Nothing went wrong,  ______ ?

21. He never takes advice,   ______?

22. I am too impatient,  __________ ?

23. Don't drop that vase,  __________ ?

24. Let's go out tonight,   ____________?

25. Open the door,  __________?

Biết sin48$°$ $\approx$ 0.7431 . Tính sin42$°$

cho tam giác ABC trên AB lấy điểm D E sao cho AD=AE qua D và E kẻ các đường thẳng song song với BC chúng cắt AC thứ tự ở M N qua N kẻ đường thắng song song với AB cắt BC ở F cm
a BE=BF 
b tam giác ADM = tam giác NFC 
c AE=EC

Tìm số giá trị nguyên của m để phương trình $x^3-3 x^2+1-m=0$có 3 nghiệm phân biệt

Ruồi giấm bộ nhiễm sắc thể lưỡng bội 2n=8 có 15 tế bào mầm sinh dục nguyên phản liên tiếp 1 số lần bằng nhau môi trường cung cấp 7560 nhiễm sắc thể mới tương đương 

a,hãy cho biết trong các tế bào lần  nguyên phân cuối cùng số nst ở kỳ trung gian? Số tâm động ở kỳ giữa ? Số nst ở kỳ sau ? Số cromatit ở kỳ sau ?

b. Nếu số tế bào trên đều chuyển sang  vùng chín.giảm phân bình thường tạo giao tử .tính số giao tử đc tạo thành?

Câu 2: Chọn các cụm từ trong ngoặc (không đều, cực, cực Bắc, cực Bắc và Nam, xích đạo) và điền vào các chỗ chấm trong câu dưới đây cho phù hợp.

Trên Trái Đất lượng mưa phân bố( 1)……………..từ Xích Đạo về( 2)……………Mưa nhiều nhất ở vùng( 3)………………., mưa ít nhất là hai vùng( 4)…………………….

Hãy xác định tọa độ địa lý của một địa danh lịch sử nằm trong vùng nội chí tuyến biết độ cao của mặt trời lúc giữa trưa vào ngày 22/6 là 83333307 và địa điểm này có giờ sớm hơn GMT là 7h7p18s Tìm tọa độ địa lý ( cho bt cách tính ) ? Và địa điểm đó thuộc địa danh lịch sử nào ? giúp em vs