Giải chi tiết từng bước cho mình phương trình và hệ phương trình này nha

\(\sqrt{8x^2-8x+3}+\sqrt{12x^2-12x+7}=2\left(-2x^2+2x+1\right)\)

\(\left\{{}\begin{matrix}xy-2y+x=2y^2\\x+\sqrt{y+1}=4\end{matrix}\right.\)

Giải phưong trình:

\(\sqrt{2x^2+6x-8}+\sqrt{2x^2+4x-6}-3\sqrt{x+4}=3\sqrt{x+3}+1\)

hộ e nha

III. Choose the best answer to complete these following sentences.

1. You can't have both of these products. Take one __________ the other.

A. and B. with C. but D. or

2. Ba really wants to buy new tables and chairs. ___________, new furniture costs too much.

A. However B. But C. Therefore D. So

3. If the TV is always on in your house, you will not reduce the ________ of electricity you use.

A. number B. amount C. much D. plenty

4. "I suggest fixing the dripping faucet." "__________"

A. We will. B. Good idea! C. Yes, please. D. I'm afraid not.

5. Lan spoke English _________ after she lived in England for several months.

A. nature B. natural C. naturally D. unnaturally

6. There's nothing good on TV. Why don't you turn it _________?

A. on B. down C. off D. up

7. I'm trying to cut down ____________ the amount of driving I do to save energy.

A. off B. to C. out of D. on

8. They wrote _______________ the addresses so that they could get in touch.

A. down B. out C. in D. on

9. They climbed onto the wall and they couldn't get _______________.

A. down B. on C. in D. over

10. _______________he has been absent frequently; he has managed to pass the test.

A. Because B. Because of C. But D. Though

11. Mary will take a plane _______________ she dislikes flying.

A. even though B. because C. and D. in spite of

12. She drank it to keep herself warm _______________ she dislikes coffee.

A. although B. because C. because of D. despite

13. The children like to put _______________ nice clothes when they go out.

A. in B. off C. into D. on

14. Before you go to bed, please turn _______________ all the lights.

A. off B. on C. in D. over

15. Please turn _______________ the gas, I want to cook my lunch.

A. over B. back C. on D. in

16. I like bananas, _______________ my brother doesn't.

A. because B. but C. and D. even though

17. I shall go _______________ you stay here.

A. and B. because C. however D. although

18. Jane will be admitted to the university _______________ she has bad grades.

A. because B. even though C. because of D. but

19. _______________ his physical handicap, he has become a successful businessman.

A. Although B. Despite C. Because of D. Because

20. She was absent _______________ her cold was worse.

A. because B. or C. because of D. so

21. The examination was long _______________ difficult.

A. or B. and C. but D. however

22. John was ill, _______________ he went to bed early.

A. but B. so C. because of D. however

23. I'd love to play the table tennis _______________ I have to complete an assignment.

A. and B. so C. but D. or

24. He likes to travel, _______________ so does she.

A. and B. or C. but D. therefore

35. The new models are expensive, _______________ efficient.

A. however B. therefore C. and D. but

26. He failed his examination. _______________; she will have to do the examination again.

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

27. Students have to carry __________ their duties.

A. out B. in C. for D. over

28. He ate the chocolate cake _________ he is on a diet.

A. in spite of B. because C. despite D. even though

29. She attended the class __________ she didn't feel alert.

A. because B. although C. so D. and

30. Classes will be canceled tomorrow _________ it is a national holiday.

A. therefore B. because C. but D. because of

31. _________ her mother's sickness, she couldn't attend our wedding.

A. As of B. Because of C. Because D. Since

32. It can be black, white __________ gray.

A. or B. however C. but D. so

33. Is it a boy _________ a girl?

A. and B. but C. or D. therefore

34. Internet is a very fast __________ convenient way for us to get information.

A. and B. therefore C. or D. but

35. He is going to collect all the bags _________ take them to the garbage dump.

A. or B. and C. however D. but

36. He likes her a lot. _________; he wouldn't keep calling her.

A. and B. however C. or D. so

37. Yesterday, he gave __________ his evening job.

A. on B. in C. up D. for

38. It was still painful, __________ I went to see a doctor.

A. but B. so C. or D. however

39. In Western countries, electricity, gas, __________ water are not luxuries but necessarities.

A. and B. or C. but D. therefore

44. The examination tested both listening __________ reading.

A. or B. and C. but D. however

41. It is raining, ________ I can't go to the beach.

A. so B. but C. or D. and

42. If you _________ complaining, I'll leave immediately.

A. go off B. go for C. go on D. go over

43. Go _________ until you get to the junction and turn left.

A. out B. on C. back D. ahead

44. He took _________ my wet boots and made me sit by the fire.

A. on B. after C. over D. off

45. May I borrow your dictionary? I want to _________ this word.

A. take up B. go up C. look up D. come up

46. Lan suggested ________to the zoo at weekend.

A.to go B. going C. went D. to go

47. Shall we clean up the kitchen, Mum? ________

A. Yes, we do B. O.K C. No, we don't. D. Yes, let's

48. It 's so hot. Why don't we go swimming? ________

A. Yes, we do B. No, we don't C. That's a good idea. D. Yes, thanks

49. Let's go somewhere for a drink________

A. All right B. Yes, we do C. No, we don't. D. No, thanks

50. This movie is not interesting. How about ________ to the concert.

A. to go B. going C. go D. went

Có các dãy chất:

+)Dãy 1:CH4,CH3-CH3,CH3-CH2-CH3 ......

+)Dãy 2:CH2=CH2,CH2=CH-CH3,CH2=CH-CH2-CH3......

+)Dãy 3:CH\(\equiv\)CH,CH\(\equiv\)C-CH3,CH\(\equiv\)C-CH2-CH3........

a)Viết cấu tạo phân tử của các chất trong các dãy trên

b)Viết công thức tổng quát của mỗi dãy

c)Viết PTHH đốt cháy của các công thức tổng quát mỗi dãy trên và rút tỉ lệ \(\dfrac{nCO2}{nH2O}\)theo từng phương trình

Cho đường tròn (O;R) và điểm A sao cho OA=2R.Vẽ các tiếp tuyến AB,AC với đường tròn (O),B và C là các tiếp điểm .Vẽ đường kính BOD của đường tròn (O).

a)Chứng minh DC song song OA

b)Đường trung trực của BD cắt AC và DC lần lượt tại M và N .Chứng minh tứ giác OCNA là hình thang cân

c)Gọi I là giao điểm của tia OA với đường tròn (O).Chứng minh MI là tiếp tuyến của đường tròn (O)

d)Tia MI cắt AB tại K.Chứng minh tứ giác AKOM là hình thoi.Tính diện tích tứ giác AKOM theo R

Bài tập:Tìm m để phương trình

a)x²+2mx-m²+m-3=0 nhận x=2 là nghiệm.Tìm nghiệm còn lại

b)2x²-4x+3m-5=0 nhận x=-1 là nghiệm.Tìm nghiệm còn lại

c)x²+(m-2)x-m+1=0 nhận x=2018+\(\sqrt{2019}\)

^{làm nghiệm}

d)x²-2(m-1)x+m²-2m-3=0 nhận x=2004-2\(\sqrt{113}\) làm nghiệm