Bài 5:

\(\dfrac{40}{x-30}=\dfrac{20}{y-15}=\dfrac{28}{z-21}\\ \Rightarrow\dfrac{x-30}{40}=\dfrac{y-15}{20}=\dfrac{z-21}{28}=k\\ \Rightarrow\dfrac{x}{40}-\dfrac{3}{4}=\dfrac{y}{20}-\dfrac{3}{4}=\dfrac{z}{28}-\dfrac{3}{4}\\ \Rightarrow\dfrac{x}{40}=\dfrac{y}{20}=\dfrac{z}{28}=k\left(đặt.k\right)\\ \Rightarrow x=40k;y=20k;z=28k\)

Mà \(xyz=22400\Rightarrow22400k^3=22400\)

\(\Rightarrow k^3=1\Rightarrow k=1\Rightarrow\left\{{}\begin{matrix}x=40\\y=20\\z=28\end{matrix}\right.\)

 My family have 4 people. There are my mother,my father,my elder sister and me.My parents are both the same age, 50 years old.My father is a teacher ,he is very kind and hard-working. My morther is a nurse, she is interesting, I think she is the most funny person in my family. My elder sister is 18 years old, she is a student and she is very pretty,she not only learns well but also plays the piano very well, I think she will become a pianist in the future. And me, I’m 16 years old and I’m a pupil, in the future i'll be a marketing staff. I love my familly very much.For me, family always is the assured a reliable support.

Hello every body ! My name is Duy . I am 14 years old . There are 5  people in my family : My father ; my mother ; my older sisters and me . My father is a doctor . He works a hospital in the city center . Every day , he go to work by bus . My mother is a teacher . She learns English at a school near my house . She walks to school every day . I have 2 elder sister . The oldest is a secretary in a company . The younger is a studente . She is learning at Hanoi university . I love my family so much . I feel very happy to be alive in this family.

                                                   My Family :

 As you know , all of us have a faimly.The family is the place we are brought up and look after everyday. Today , I would like to introduce my topic is " My Family"

 I come from a family of 4 people : my parents , my younger brother and me.

 My father is an engineer. He likes reading new spaper and watching TV.He teaches me many helpfull things in the life : know how to love everyone , how to behave well , how to keep clothes and schoolthings clean and tidy , ect .....But sometimes when I make mistakes , he is very strict but frankly my father is so kind and friendly.

 And my mother is a teacher.She is a good woman. She is very carefull.My mother cooks very well.My brother and I like eatiing her dishes very much especially fried chicken , and so on... My parents love me and my younger brother so much but they don't say.

 And my brother is a good student at Nguyen Ngoc Binh Primary School.He is a active boy in many activities as well as studying. When my brother and I have free time, we often play many many sports and games such as : badminton , volleyball , hide - and - seek , ect....

 And my name is Nhi. I'm a student at class 6/1 at Tran Phu Secondary School. I'm very good at English.

 When all the members in my family have free time , we usually talk about studying as well as working together.Also , I can have meats with my family.I'm so happy and really fun so much. At the weekend , we visit many places such as : park , zoo , beach , ....  I love all the people in my family.

 So being a member of my family , I will try my best to study well to become a good daughter . And my parents will be proud about me.

tra google nhá

Want to learn better English 8, needs to investigate more words in the dictionary he Vietnam. The school in the dictionary helps us in many vocabularies, learn many new words. Also, the help of reading have the knowledge to do the questions in English, helps us have better communication skills. Collective listening, speaking, reading and writing to do well as much more. Go online to help us investigate the things that we do not know, the information that we do not know will be answered.

Want to learn better English 8, needs to investigate more words in the dictionary he Vietnam. The school in the dictionary helps us in many vocabularies, learn many new words. Also, the help of reading have the knowledge to do the questions in English, helps us have better communication skills. Collective listening, speaking, reading and writing to do well as much more. Go online to help us investigate the things that we do not know, the information that we do not know will be answered.

I was born and grown up on the poor land in Duc Tho district, Ha Tinh province. That’s where deeply attaches to me 24 years of life. If anyone who asks me that “What’s the thing your most proud of?” .I will answer that’s my hometown. Duc Tho is the land poor where the people live by rice cultivation, breeding, and fishing. Although the life is very difficult, but the people is very friendly, and studious. In Duc Tho, there is a Tung Anh village where called “Doctor village”. Duc Tho is also the home of Tran Phu Secretary General, and marked many memories of the great leader Ho Chi Minh.

If you come to Duc Tho, you will feel many interesting things, visiting Tran Phu tombstone, La Giang dyke, rowing on La driver, and enjoying the traditional songs. In the evening, they can enjoy a special food which is “mussel rice” – just only eat one time, you will never forget.

Beautiful and unobtrusive! Duc Tho always tries to grow, and to improve the life of people, but keeping the traditional culture.

I was born and grown up on the poor land in Duc Tho district, Ha Tinh province. That’s where deeply attaches to me 24 years of life. If anyone who asks me that “What’s the thing your most proud of?” .I will answer that’s my hometown. Duc Tho is the land poor where the people live by rice cultivation, breeding, and fishing. Although the life is very difficult, but the people is very friendly, and studious. In Duc Tho, there is a Tung Anh village where called “Doctor village”. Duc Tho is also the home of Tran Phu Secretary General, and marked many memories of the great leader Ho Chi Minh.

If you come to Duc Tho, you will feel many interesting things, visiting Tran Phu tombstone, La Giang dyke, rowing on La driver, and enjoying the traditional songs. In the evening, they can enjoy a special food which is “mussel rice” – just only eat one time, you will never forget.

Beautiful and unobtrusive! Duc Tho always tries to grow, and to improve the life of people, but keeping the traditional culture.

Almost people say that they prefer living in the peaceful countryside to the noisy city. I agree with them but I can't admit it when I live here-my second hometown-Tay Ninh. Although Tay Ninh is now a city but it's very peaceful and comfortable. I can hardly hear any loud noise and you know, to me, the most peaceful place is my neighborhood.

My family and my neighbors live together on Dien Bien Phu Street. Every morning when I get up, I always can see the sun shining and there are some warm voices from the small beautiful birds and the sounds from my neighborhood. We all get up very early. A new day begins. I often wander around my neighborhood. There are lots of green trees along the streets. There, we can see a range of houses from high to short, ordinary to extraordinary. We all do business. Some neighbors sell foods, drinks and household appliances as grocery stores. Some are tailors who mend clothes, make clothes and mend shoes too. Some are the barbers who cut hair and give make up my mother. Some are bakers who bake cakes in the bakery and sell breads. The environment is never polluted and we can feel the warm atmosphere everytime.

All the inhabitants in my neighbor are very friendly to each other. Whenever a person needs help, the others are always ready to give help and one thing should be mostly appreciated is that they never mind how difficult the work is. And we build such a great consolidation. When a neighbor has just returned from a trip, they always remember to buy the others some beautiful and worthy gifts and we also share the money for parties together. We never underestimate the honor we give each other.

I love my neighborhood very much. I hope that our friendliness and consolidation will last forever and remain unchanged.

 nha bn Sư Tử nóng tính !

Bài 1: 

AB;AC;AD;BC;BD;CD