K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

31 tháng 8 2021

Trả lời:

\(a,\sqrt{\left(11-6\sqrt{2}\right)^2}+\sqrt{\left(11+6\sqrt{2}\right)^2}\)

\(=\left|11-6\sqrt{2}\right|+\left|11+6\sqrt{2}\right|\)

\(=11-6\sqrt{2}+11+6\sqrt{2}\)

\(=22\)

b, \(\sqrt{\left(10-4\sqrt{6}\right)^2}-\sqrt{\left(10+4\sqrt{6}\right)^2}\)

\(=\left|10-4\sqrt{6}\right|-\left|10+4\sqrt{6}\right|\)

\(=10-4\sqrt{6}-\left(10+4\sqrt{6}\right)\)

\(=10-4\sqrt{6}-10-4\sqrt{6}\)

\(=-8\sqrt{6}\)

c, \(\sqrt{\left(4-\sqrt{5}\right)^2}+\sqrt{\left(1-\sqrt{5}\right)^2}\)

\(=\left|4-\sqrt{5}\right|+\left|1-\sqrt{5}\right|\)

\(=4-\sqrt{5}+\sqrt{5}-1\)

\(=3\)

d, \(\sqrt{\left(7+\sqrt{2}\right)^2}-\sqrt{\left(1-\sqrt{2}\right)^2}\)

\(=\left|7+\sqrt{2}\right|-\left|1-\sqrt{2}\right|\)

\(=7+\sqrt{2}-\left(\sqrt{2}-1\right)\)

\(=7+\sqrt{2}-\sqrt{2}+1\)

\(=8\)

31 tháng 8 2021

Trả lời:

Bài 2:

a, \(5\sqrt{25a^2}-25a\) với \(a\le0\)

\(=5\sqrt{\left(5a\right)^2}-25a\)

\(=5.\left|5a\right|-25a\)

\(=5.\left(-5a\right)-25a\) (vì \(a\le0\))

\(=-25a-25a=-50a\)

b, \(\sqrt{49a^2}+3a\) với \(a\ge0\) 

\(=\sqrt{\left(7a\right)^2}+3a\)

\(=\left|7a\right|+3a\)

\(=7a+3a\) (vì \(a\ge0\))

\(=10a\) 

c, \(\sqrt{16a^4}+6a^2\)

\(=\sqrt{\left(4a^2\right)^2}+6a^2\)

\(=\left|4a^2\right|+6a^2\)

\(=4a^2+6a^2=10a^2\)

d, \(3\sqrt{9a^6}-6a^3\) với \(a\le0\)

\(=3\sqrt{\left(3a^3\right)^2}-6a^3\)

\(=3.\left|3a^3\right|-6a^3\)

\(=3.\left(-3a^3\right)-6a^3\) (vì \(a\le0\))

\(=-9a^3-6a^3=-15a^3\)

6 tháng 12 2021

\(1.Ca+2HCl->CaCl2+H2\)

\(2.H2+Cl2->2HCl\)

\(3.2Mg+O2->2MgO\)

\(4.FeO+C0->Fe+CO2\)

6 tháng 12 2021

câu 4 hình như chx được cân bằng lắm

15 tháng 12 2021

a. Chu vi là \(\left(12+5\right).2=34\left(m\right)\)

Diện tích là \(12.5=60\left(m^2\right)=600000\left(cm^2\right)\)

b. Cần lát \(600000:\left(40.40\right)=375\) viên gạch

a) Chu vi lối đi là :

( 12 + 2 ) x 2 = 28 ( m )

Diện tích lối đi là :

12 x 2 = 24 ( m2 )

b) Diện tích 1 viên gạch là :

40 x 40 = 1600 ( cm2 ) = 0,16 m2

Cần số viên gạch là :

24 : 0,16 = 150 ( viên )

16 tháng 10 2021

Bài 1:

a) Nhẹ hơn

b) Nhẹ hơn

c) Nặng hơn

d) Nhẹ hơn

16 tháng 10 2021

Bài 2:

a) Ta có: \(M_X=16\cdot2=32\left(đvC\right)\)

  Vậy X là Lưu huỳnh  (S)

b) Nhẹ hơn

c) 16 hạt

d) 17 hạt

26 tháng 12 2021

khôn lõi:)

26 tháng 12 2021

Câu 5: D

Câu 7: A

12 tháng 9 2021

\(B=2+2^2+2^3+2^4+...+2^{99}+2^{100}=2\left(1+2^2+2^3+2^4\right)+...+2^{96}\left(1+2^2+2^3+2^4\right)=2.31+2^6.31+...+2^{96}.31=31\left(2+2^6+...+2^{96}\right)⋮31\)

Cảm ơn bạn/chị nhé ạ!!!Thankyou very much!!!

 

AI CHỈ MÌNH VỚI MÌNH CẢM ƠN AI GIÚP MÌNH VỚI MÌNH CẢM ƠN NHIỀU21. Hoa looks red. She was outdoors yesterday. Perhaps she has _______                                                  A. flu                           B. sunburn                   C. spots                       D. stomachache22. My family has decided to use _________ electricity by using more solar energy instead.                     A. more                       B. less                          C....
Đọc tiếp

AI CHỈ MÌNH VỚI MÌNH CẢM ƠN
 

AI GIÚP MÌNH VỚI MÌNH CẢM ƠN NHIỀU

21. Hoa looks red. She was outdoors yesterday. Perhaps she has _______                                                  

A. flu                           B. sunburn                   C. spots                       D. stomachache

22. My family has decided to use _________ electricity by using more solar energy instead.                     

A. more                       B. less                          C. much                       D. fewer

23. I ............... playing board games interesting because I can play them with my friends.                         

A. find                                    B. think                       C. say                          D. tell

24. Circle the word that has the underlined part pronounced differently from the others.                          

A. curl                         B. keen                        C. city                         D. cook

25. I …………….. Nha Trang when I was a child.                                                                                      

      A. visit                              B. visited                     C. will visit                  D. have visited

26. He …………… to the USA so far.                                                                                                         

      A. is                                   B. was                         C. will be                     D. has been

27. Americans eat a lot of junk food, ………….junk food causes obesity.                                                  

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

28. Tim: I feel itchy and my nose is running. Doctor: ………………………..                                            

      A. Wash your hair more.                                       B. I think you have the flu.

      C. Drink more water. Eat less meat                      D. I think you have a stomachache.

29. Pick out the word whose main stress is placed differently from the others.                                           

      A. allergy                          B. headache                C. temperature           D. obesity 

30. Choose the word that has the underlined part pronounced differently from the others.                        

      A. cold                              B. curly                       C. ocean                     D. clothes

31. -“What would you like to drink now?”    - “_______________.”                                                          

            A. No, thanks              B. Yes, please             C. I like to do nothing            D. Orange juice, please

32. All of us enjoy _______ to classical music.                                                                                             

            A. listen                       B. listens                     C. listening                  D. listened

33. She worked very hard,  _______she passed all  her exams.                                                                    

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

35. -“ Would you like me to turn off your computer?                                                                                   

    - “ ______________. I’ll do it myself”

            A. No, thanks              B. Yes, please             C. Don’t do it             D. Of course

PART B. WRITING

I. Put the verbs in the correct form.
1. I enjoy (fish) .................................................. because it (be) ……………….… relaxing.                       
2. Jane will play chess after she (finish) …………………………. school.                                                  

3. What …………………… your mother often (do) ………………………at weekends?                         

4. I think, in the future people (not play) ………………………………… individual games.                    

5. We find (arrange) ……………………… flowers interesting because it (help) ……………… us relax. 

6. I (not collect) ………….……………………… dolls when I grow up.                                                   

7. She often (go) ......................... to the market with her mother every weekend.                                       

8. We (visit) ...................... Hue next month.                                                                                                            

9. My younger sister (collect) ................. dolls two years ago.                                                                     

10. .................. you ever (do) ................. volunteer work ?                                                                           

II. Arrange these words/ phrases into the meaning sentences

1. sunburn / yesterday / was / because / outside / has / Alice / she / all / day .                                               

……………………………………………………………………………………………..

2. and / difficult / boring / that / eggshells  / people / carving / Some / say / is                                              

..…………………………………………………………………………………………..

3. girl / have / is / the / kind-hearted /  She / most / ever / I /met                                                                   

……………………………………………………………………………………………..

4. organization / the / to / encouraged / people /  Big Heart / has / protect / environment.                            

……………………………………………………………………………………………..

III. Write full sentences using the suggested words and phrases given.

1.Tuan / find / play / table tennis / interesting / because / he / can / play / best friends.                                

…………………………………………………………………………………………

2.They / visited / Ho Chi Minh City / so far.                                                                                                 

…………………………………………………………………………………………

3.Lan / like / talk / to / her friends / her free time.                                                                                         

…………………………………………………………………………………………

4. We/ not eat/ out/ since/ mom’s birthday.                                                                                                   

…………………………………………..

5. How/ long/ you/ live/ here?                                                                                                                        

…………………………………………..

6. You/ ever/ been/ Russia?                                                                                                                            

…………………………………………..

7. She/ not/ meet/ kids/ since Christmas.                                                                                                       

…………………………………………..

8. They/ repair/ lamps/ yet?                                                                                                                            

…………………………………………..

IV. Complete each sentence so it means the same as the sentence above.

1. I didn’t go to school because I was sick.                                                                                       

à I was sick, so …………………………………………………………………

2.It will be good if you eat less meat and more vegetables.                                                                          

à You should ………………………………………………………………………

3. He likes playing computer games in his free time.                                                                                     

à His hobby is ……………………………………………………………………..

4. I am interested in watching TV in the evening.                                                                                         

à I enjoy ………………………………………………………………………

5.I think that learning English is important.                                                                                                  

à I find ……………………………………………………………………………..

6. He started working as a bank clerk 3 months ago.                                                                                    

=> He has.................................................................................................................

7. I last had my hair cut in November.                                                                                                          

=> I haven't................................................................................................................

8. The last time we called each other was 5 months ago.                                                                              

=> We haven't.............................................................................................................

 

2
18 tháng 12 2021

21. Hoa looks red. She was outdoors yesterday. Perhaps she has _______                                                  

A. flu                           B. sunburn                   C. spots                       D. stomachache

22. My family has decided to use _________ electricity by using more solar energy instead.                     

A. more                       B. less                          C. much                       D. fewer

23. I ............... playing board games interesting because I can play them with my friends.                         

A. find                                    B. think                       C. say                          D. tell

24. Circle the word that has the underlined part pronounced differently from the others.                          

A. curl                         B. keen                        C. city                         D. cook

25. I …………….. Nha Trang when I was a child.                                                                                      

      A. visit                              B. visited                     C. will visit                  D. have visited

26. He …………… to the USA so far.                                                                                                         

      A. is                                   B. was                         C. will be                     D. has been

27. Americans eat a lot of junk food, ………….junk food causes obesity.                                                  

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

28. Tim: I feel itchy and my nose is running. Doctor: ………………………..                                            

      A. Wash your hair more.                                       B. I think you have the flu.

      C. Drink more water. Eat less meat                      D. I think you have a stomachache.

29. Pick out the word whose main stress is placed differently from the others.                                           

      A. allergy                          B. headache                C. temperature           D. obesity 

30. Choose the word that has the underlined part pronounced differently from the others.                        

      A. cold                              B. curly                       C. ocean                     D. clothes

31. -“What would you like to drink now?”    - “_______________.”                                                          

            A. No, thanks              B. Yes, please             C. I like to do nothing            D. Orange juice, please

32. All of us enjoy _______ to classical music.                                                                                             

            A. listen                       B. listens                     C. listening                  D. listened

33. She worked very hard,  _______she passed all  her exams.                                                                    

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

35. -“ Would you like me to turn off your computer?                                                                                   

    - “ ______________. I’ll do it myself”

            A. No, thanks              B. Yes, please             C. Don’t do it             D. Of course

18 tháng 12 2021

I. Put the verbs in the correct form.
1. I enjoy (fish) ........................fishing.......................... because it (be) ……is………….… relaxing.                       
2. Jane will play chess after she (finish) …………finishes………………. school.                                                  

3. What ……………does……… your mother often (do) ………do………………at weekends?                         

4. I think, in the future people (not play) ……………won't play…………………… individual games.                    

5. We find (arrange) ………arranging……………… flowers interesting because it (help) ………helps……… us relax. 

6. I (not collect) ………….won't collect……………………… dolls when I grow up.                                                   

7. She often (go) ..........goes............... to the market with her mother every weekend.                                       

8. We (visit) ...........will visit.......... Hue next month.                                                                                                            

9. My younger sister (collect) ........collected......... dolls two years ago.                                                                     

10. ..........Do........ you ever (do) ........do......... volunteer work ?                                                                           

 

23 tháng 10 2021

c. Sụn tăng trưởng ở hai đầu xương