`a) -(a+b-c+d)+(a+b-c+d)`
`=-a-b+c-d+a+b-c+d`
`=0`
Vậy `-(a+b-c+d)+(a+b-c+d)=0`
`b) a(b-c-d)-a(b+c-d)`
`=ab-ac-ad-ab-ac+ad`
`=-2ac`
Ko so sánh đc
Hãy đọc kĩ đoạn văn và sửa lại chính tả cho đúng My best friend in high school is Lan. Lan sits next to me in class, eats with me at break time, and hangs out with me after school. She has beautiful and long hair; my mother always says that I need to pay more attention to my hair so it can be pretty as hers. I am good at English while Lan is excellent in Math, therefore we can help each other every time one of us has trouble in understanding those subjects. Besides our study, Lan is always by my side whenever I feel upset. I tell her everything, and only she can know my true feelings. We have been best friends since our young age, and I will keep this friendship forever.
Q14: Give the correct form of the verbs in brackets: Mr. Thang _____________ (not teach) us Robotics last year. * A.doesn’t teach B.didn’t teach C.hasn’t taught D.haven’t taught Mục khác: Q15: Give the correct form of the verbs in brackets: ___________ (robots/ do) things that people can’t do or don’t want to do in the future? * A.Will robots do B.Do robots do C.Shall robots do D.Does robots do Mục khác: Q16: Give the correct form of the verbs in brackets: Miss Ha _____________ (be) to Ha Long Bay three times. * A.have been B.had been C.was D.has been Mục khác: Q17: Give the correct form of the words in the brackets in each of the following sentences: This bag is ___________so don't throw it away after using. (reuse) * A.reused B.reusably C.unreusable D.reusable Mục khác: Q18: Give the correct form of the words in the brackets in each of the following sentences: He was a talented _________. He created many great buildings in big cities. (design) * A.designer B.designing C.designnation D.designed Mục khác: Cứu 5 câu chọn đáp án
Khí trơ là gì? Hoặc môi trường trơ là gì? Giải thích đừng theo nghĩa hóa học như ở nhóm nào đâu đó
CMR: ( x + y)3 = x(x - 3y )2 +y( y –3x )2
ai cứu mình với cần gấp lắm lắm rồi ạ
giúp mình bài này với mọi người
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1. Most ethnic peoples of Vietnam ………………….their own languages. A. tell B. speak C. do D. improve 2. This group of people has many traditional…………. such as weaving, embroidery. A. crafts B. minorities C. festivals D. costumes 3. This object ……………….an important role in the family for Cham ethnic people. A. has B. gives C. finds D. plays 4. If you want to have an overview of the ethnic groups of Vietnam, you should visit the ……………………of Ethnology. A. cinema B. theatre C. museum D. market 5. The museum has a lot of information about different ethnic……………in Vietnam. A. festivals B. peoples C. projects D. programs 6. What is the ……………………of the biggest group? About 80 million people. A. benefit B. size C. population D. task 7. Some ethnic groups ……………….. semi-nomadic life many years ago. A. took B. lived C. made D. gave 8. We understand deeply the ……………………values of different ethnic groups. A. cultural B. national C. local D. international 9. Ethnic groups have established good…………….and cooperation with each other. A. task B. relation C. friend D. neighbor 10. The communal house is usually the largest and ………..…..building in the village. A. smallest B. newest C. cheapest D. tallest
Giúp mình với câu 13, 14 với ạ đang cần gấp cảm ơn nhiều
Giúp e vs mn ơi!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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