Ta có : 2x = 5y \(\Rightarrow\frac{x}{5}=\frac{y}{2}\Rightarrow\frac{x^2}{25}=\frac{y^2}{4}\)

Áp dụng t/c của dãy tỉ số bằng nhau, ta có :

\(\frac{x^2}{25}=\frac{y^2}{4}=\frac{x^2+y^2}{25+4}=\frac{133}{29}\)

Suy ra :

+) \(\frac{x^2}{25}=\frac{133}{29}\Leftrightarrow x^2=\frac{3325}{29}\Leftrightarrow x=\sqrt{\frac{3325}{29}}\approx10,7\)

+)\(\frac{y^2}{4}=\frac{133}{29}\Leftrightarrow y^2=\frac{532}{29}\Leftrightarrow y=\sqrt{\frac{532}{29}}\approx4,3\)

Vậy \(x\approx10,7;y\approx4,3\)

1 Đặt câu hỏi cho các từ được gạch dưới
1. His telephone number is 38 259 640.

Is his phone number 38 259 640?

2. It's about two kilometers from my house to the movie theater

Is it 2 km from my house to the cinema?

3. I will go camping next Sunday

Will I go camping next Sunday?

4. Her date of birth is on August 21^st

Is her birthday August 21th?

5. She will be fourteen on her next birthday

She will be fourteen on her next birthday,right?

6.My father is an engineer.

Is his an engineer?

7. They live at 2/10B Ly Thuong Kiet Street.

They live in 2/10B Ly Thuong Kiet, right?

8. John is talking to Nhat

John's talking ther with Nhat?

1. His telephone number is 38 259 640.

-> what's his phone number?

2. It's about two kilometers from my house to the movie theater

->How long is it from your house to the movie theater?

3. I will go camping next Sunday

-> When will you go camping?

4. Her date of birth is on August 21^st

^->when was she born

5. She will be fourteen on her next birthday

_>When will she be 14 years old?

6. My father is an engineer

->What does your father do?

7. They live at 2/10B Ly Thuong Kiet Street.

-> where do they live?

8. John is talking to Nhat

->Who is talking to Nhat?

1. will come

2. doesn't drink

3. go / will catch

4. is playing

5. don't go / go

6. to visit

7. taking

8. did / do / is cooking

1. will come

2. doesn't drink

3. go - will catch

4. is playing

5. won't go - will go

6. to visit 

7. taking

8. is - do - is cooking

Tk mk nha

1 many 

2 illiterate

3 people

văn bản của bạn được viết bằng anh-anh nên mình sẽ viết cho bạn một văn bản bằng anh mỹ nhé:

Every country has many people who voluntarily take care of others. No matter who you are and how old you are, you do volunteer work. There are a lot of volunteer work such as visiting the elderly, sick, teaching poor children, however, have you ever thought about why people do volunteer work? It certainly has many reasons for it. In my opinion, there are five main reasons why people do volunteer work. The first reason, I think it is the humanity. People who feel lucky and have a good life, know how to share the feelings of the poor, the injured, the disabled ... etc. Therefore, they want to share with them their difficulties and sorrows, help them. can help them get through the troubles. They want to bring happiness to poor and disabled children as well as boys without fathers and mothers without mothers. They want to help these kids go to school and teach them what they usually learn from their parents. Besides, they take care of the elderly and the sick because they consider them as their relatives, hoping to help them overcome loneliness and sickness. They also want their kids to be human. They teach them to love and help others. Second, people do volunteer work because it's their hobby in their spare time, perhaps ”. Instead of listening to music or playing games… .. we to do volunteer work. It's really fun and we can help others, too. Some people have shared. Third, some people do it because it's their job. These people often work in volunteer organizations. They get paid for it. The fourth reason is that people not only want to help, but they also prace their ability in social activities, volunteering. They think that it can both help others and train themselves. They also find friends or people who them. In the end, people volunteer because they think that the happiest people in the world are the ones who help make others happy.

giúp mik với mn ơi

bằng tiếng anh nha. 

:))))

Dài khoảng bao nhiêu bạn?

vsqgdôdldllddldldlllllllllllllllllllllwwwww hello he jdưdq

1.have you been 

 2.did you go

3.have you ever been

4.did you go

5.have he done

6.have not finished

7.did you play

8.have you ever played

9.have not ever been

10.how did you usually spend /was/

1 Are inquires about the thief being made by the police ?

->  Is the police making inquires about the thief?

2. Must this machine the used before 5:30 p.m by us?

-> Must we use this machine before 5:30 p.m  ?

* Kiểm tra lại ~

1. Read less books and you can learn new things.

.............less--> more..........................................................................................

2. Talk more and keep quiet. I need to concentrate on my homework.

.................more--->less.............................................................................................

3. Spend more time on computer and hang out more with friend.

................more---->less...........................................................................

4.Eat less carrots because they are good for your eyes.

..............less--->more.......................................................................

Gạch lỗi sai trong các câu sau rồi sửa lại cho đúng:

1. Read less books and you can learn new things.

.....more..................................................................................................

2. Talk more and keep quiet. I need to concentrate on my homework.

.......less.......................................................................................................

3. Spend more time on computer and hang out more with friend.

.......less....................................................................................

4.Eat less carrots because they are good for your eyes.

.....more................................................................................