Giải thích các bước giải:
Câu 8:
Ta có :$11(2a+b)+3(3b-4a)=10a+20b=5(2a+4b)\quad\vdots\quad 5$
Mà $2a+b\quad\vdots\quad 5\to 3(3b-4a)\quad\vdots\quad 5$
$\to 3b-4a\quad\vdots\quad 5$
Bài 9:
Gọi số cần tìm là $x,y,(x,y\in Z)$
Theo bài ta có :$xy=x+y$
$\to xy-x-y=0$
$\to x(y-1)-(y-1)=1$
$\to (x-1)(y-1)=1$
$\to x-1,y-1$ là cặp ước của 1
$\to (x-1,y-1)\in\{(1,1),(-1,-1)\}$
$\to (x,y)\in\{(2,2),(0,0)\}$
Cách khác :
Bài 8 :
Đặt : $A=2a+b,B=3b-4a$
Ta có : $2A+B = 4a+2b+3b-4a=5b \vdots 5 $ (*)
Do đó, nếu $A \vdots 5$ thì từ (*) $⇒ B \vdots 5$
Ngược lại , nếu $B \vdots 5$ thì từ (*) $⇒ A \vdots 5$
Vậy ta có điều phải chứng minh !
Rearrange the words and phrases given to make meaning full sentences: 1.Thanks / technology/ , /now/can/for/preserve/our/to/culture/future/we/generations/./ …………………………………………………………………………………………. 2.Vietnamese /plan/activities/ famylies/ around/ their/ children/on/many/their/special/days/./ ………………………………………………………………………………………………. 3.One /popular /the/is/the/Hung Kings/Temple/festivals/in/most/festival/of/Viet Nam/./ ……………………………………………………………………………………………….. 4.In/country/our/,/government/always/the/care/takes/of/people’slife/the/,/the/groups/ethnic/especially/./ ……………………………………………………………………………………………….. 5.Nowadays/are/using/more/for/villagers/motorcycles/of/instead/riding/or/a/horse/walking/ transport/./ ……………………………………………………………………………………………….. III. Make sentences using the words and phrases given : 1. It/such/difficult/question/all/students/can/not/answer/it/./ …………………………..…………………………..………………………………………… 8 / 8 2. Because/film/so/boring/,/I/feel/asleep/./ …………………………..…………………………..………………………………………… 3. If/you/take/exercise/regularly/,/you/stay/shape/./ …………………………..…………………………..………………………………................. 4. In spite of/ be/strong/,/he /can/not/move/that/stone/./ …………………………..…………………………..………. 5,We / just / take / part / the Mid -Autumn Festival /./ …………………………..…………………………..………………………………..................……………………………….
Mọi nguoeif giúp.mình giải bài 4.28 với ạ
IV. Fill in each blank with ONE suitable preposition. 1. I'm reading a book ……………..history of China. 2. Is it far …………….your house ……… school? 3. Is Tokyo the biggest city ……………..the world. 4. John's worried ………………his final exam. 5. What's HCM city famous ………………….? 6. Her sister is working ..…….a computer company. 7. What time does the library close? It closes ……………about half …………. four. 8. We look …………the new words in the dictionary. 9. What is your date ……..birth? - November eighth. 10. Farmers are very hard - working. They work ……………. morning ………….. night on their farms. 11. Mr. Minh is not at home now. He is ………………………………work. V. Give the correct form of the verbs in brackets to complete the following sentences. 1. What ………………………you (do) ……………….at the moment? I (watch) ……………………TV. 2. We (be) ………………………………………………students in four years. 3. A little girl can't spend all her time (listen) ……………………………… to stories. 4. We (play) …………………soccer this afternoon. Would you like (join) …………………………..? 5. You can borrow my umbrella. I (not/ use) ……………………….. it at the moment. 6. Look! The plane (fly) ………………………………………. towards the airport. 7. Nam (not visit) ………………………. the museum with his class last Sunday because he had a cold. 8. We (have) ……………… a birthday party last week and a lot of people (join)………………………… VI. Put these expressions in the gaps to complete the sentences
Các bn tìm lỗi sai cho mình nhé Câu 2. Cho dãy từ "thánh thót, líu lo, tí tách, ríu rít, tíu tít, ríu ran". 4.Từ không thuộc nhóm từ đó là (3 Điểm) Thánh thót Líu lo Tí tách Tíu tít Ríu rít Ríu ran 5.Từ đó không cùng nhóm với các từ còn lại vì? (3 Điểm)
III. Choose the best option to complete the sentence. 1. Minh used to _________his homework late in the evening. ( does/ do / doing / did) 2. If people _________the rules, there are no more accidents. ( follow / take care of / obey / remember) 3. You should _________right and left when you go across the roads.( see / look / be / take) 4. Hurry up or we can’t _________the last bus home. ( keep / follow / go / catch) 5. Public _________in my town is good and cheap. ( transport / tour / journey / travel) 6. _________is not very far from here to the city centre. ( That / This / It / There) 7. When there is a traffic jam, it _________me a very long time to go home.( costs/ takes / lasts / spends) 8. Mai’s dad usually drives her to school __her school is very far from her house.( but / though/ because / or) 9. Traffic accidents can be prevented if people _______ the rules ( remember / obey / go after / take care of) 10. Hurry up, or we'll _______ the last bus. (lose / avoid / miss / drop) 11. Does your bike ever __________ down on the way to school? ( break / take / do / turn) 12. Give a __________ before you turn left or right. ( sign / turn / sound / signal)
Cho em hỏi là:trong cấu trúc động từ,tặng cho ai cái gì và tặng cái gì cho ai (động từ donate) đều dùng chung một cấu trúc đúng ko ạ
Help me help me làm nhanh lẹ lẹ lên mình đg cần gấp
II. Write the complete the sentences 1. La Tomatina / hold / the last Wednesday / August / every year.
Các bn làm giúp mk bài 5 nha mk cần gấp lắm luôn
VIII. Choose the best answer to complete the passage. When you are in Hong Kong, you can go about by taxi, by tram, by bus, or (1) (in / by / on /with ) underground. I myself prefer the underground (2) (because / when / so / but) it is fast, easy and cheap. There are (3) (some / a lot / many / few )trams and buses in Hong Kong, and one cannot drive along the road (4) (quick / quicker / quickly / quickest) and without many stops. The underground is therefore usually quicker (5) (as / than / so / like ) taxis or buses. If you do not know Hong Kong very well, it is very difficult (6) (finding / to find/ found / to finding) the bus you want. You can take a taxi, but it is (7) (more / much /as / too) expensive than the underground or a bus. On the underground you find god maps that tell you the names of the stations and show you (8) (who / when / what / how )to get to them so that it is easy to find your way.
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