Đáp án:
(-99)^199 < (-100)^200
Giải thích các bước giải:
(-99)^199 và (-100)^200
Ta có : (-99)^199 < 0 (mũ chẵn thì lớn hơn hoặc bằng 0, còn đây là mũ lẻ 199 nên nhỏ hơn 0 ) (1)
(-100)^200 > 0 (2)
Từ (1) và (2) suy ra (-99)^199 < (-100)^200
Vì `(-100)^200` là số mũ chẵn nên lũy thừa luôn luôn `≥ 0`
Và `(-99)^199` là số mũ lẻ nên lũy thừa luôn luôn ` <0`
`⇒(-99)^(199)<(-100)^200`
@`RON`
Làm giúp mình câu 5. Đúng nha. Hứa vote 5*+ cảm ơn.
x-1/2=y+2/3=z+3/3 và x-2y+3z=46
Cho dung dịch $NH_4NO_3$ tác dụng với dung dịch kiềm của một kim loại hóa trị II. Sau khi phản ứng xảy ra hoàn toàn thu được 4,48 lít khí (ở đktc) và 26,1 gam muối. Xác định kim loại.
cho dd nh4no3 tac dung voi dd kiem cua mot kim loai hoa tri ll sau khi phan ung xay ra hoan toan thu duoc 4.48 lit khi o dktc va 26.1 g muoi . kim loai do la
what the teacher does first is to check.....of the students(ATTEND) We all take pride in our.......friendship(distroy) He proposes closing down all the......factories in the area(ECONOMY) The song always brings back her lovely.......memories(CHILDREN) The article failed to......the unemployment issue(public)
Giúp mình câu 17 với ạ Trước 14h30 nha :(((
Viết 1 câu thông điệp về tác hại của bao ni lông (Ngắn)
Giải giúp em với ạ Có kèm lời giải cũng đc ạ
I. Choose the word that has the underlined part pronounced differently. 1. a. collect b. cough c. think d. certain 2. a. girl b. game c. gym d. give 3. a. colour b. face c. city d. recycle 4. a. global b. geography c. green d. big 5. a. charitable b. character c. headache d. school II. Complete the sentences with the words or phrases from the box. street children volunteers homeless people elderly people sick children disabled people donnors 1. Sally often spends her free time helping ________________ at the hospital. 2. They provide housing and other services to ________________. 3. Street Child works to help ________________ off the streets and into school. 4. Most blood ________________ are unpaid volunteers who donate blood for a community supply. 5. Schools need ________________ to help children to read. 6. They help ________________ with housework and gardening. 7. The local authority built a new home for severely ________________. III. Complete the sentences with the correct verbs in the box. plant volunteer clean up donate tutor recycle provide organise 1. ______________ your used books to your local library or charities. 2. ______________ a fundraising event to raise money for charity. 3. ______________ polluted rivers and lakes. 4. ______________ trees or flowers in your backyard or community garden. 5. ______________ at a nursing home, soup kitchen, or homeless shelter. 6. ______________ plastic and paper for a clean environment. 7. ______________ nutritious meals to the poor and needy people. 8. ______________ homeless children who are unable to attend school. IV. Underline the correct answers. 1. I saw/ have seen that film already. 2. We went/ have gone to the movies three times last month. 3. Did you ever do/ Have you ever done volunteer work? 4. I had/ have had five tests so far this semester. 5. Linus did/ has done his homework before he went to sleep. 6. This is my grandparents’ house. They lived/ have lived here for more than 50 years. 7. She bought/ has bought a new mobile phone two days ago. 8. Did you see/ Have you seen Peter at the party last night? 9. I read/ have read this book twice and I still find it very interesting. 10. They didn’t play/ haven’t played very well yesterday. They lost the match. V. Put the verbs into the correct tense, past simple or present perfect. 1. _____________ (you/ ever/ be) to the United States ? - No, but I _____________ (be) to England and France. 2. When we were in Canada, we _____________ (go) skiing almost every day. 3. When _____________ (you/ meet) your wife? - 3 years ago. 4. Peter _____________ (not phone) yet. I’m still waiting. 5. I _____________ (know) Helen since we were at school together. 6. My uncle _____________ (live) in Berlin in 1999. 7. We _____________ (not see) Beth at Mike’s house yesterday morning. 8. Do you like this picture? My uncle _____________ (paint) it. 9. Mr. Dass _____________ (leave) for New York late last night. 10. Mr and Mrs Grey _____________ (teach) French here for over five years. VI. Choose the correct answer a, b, c, or d. 1. We ______ very busy last week. a. was b. am c. were d. will be 2. I ______ her recently. The last time we met was at a party. a. have seen b. haven’t seen c. didn’t see d. saw 3. In 2012, they ______ their project for street children. a. start b. are starting c. started d. have started 4. We ______ very early this morning. a. will leave b. leave c. have left d. left 5. She ______ because she’s late for her class. a. runs b. ran c. is running d. has ran 6. I ______ that book already. It’s really fantastic. a. read b. have read c. am reading d. will read 7. He ______ you as soon as he’s on the bus. a. will call b. calls c. called d. is calling 8. Sometimes I ______ up the streets of my neighborhood for volunteer service. a. clean b. am cleaning c. have cleaned d. will clean 9. I live in New York, but I ______ the Statue of Liberty. a. never visit b. have never visited c. never visited d. will never visit 10. I ______ my favourite song when I turned on the radio yesterday. a. hear b. heard c. am hearing d. will hear VII. Join each pair of sentences using because, as or since. 1. He stopped the car. The traffic lights turned red. (because) 2. Jane didn’t join our programme. She had to take a summer course. (as) 3. He behaved very rudely. Everyone dislike him. (since) 4. They like doing something useful. They do volunteer work. (because) 5. I won’t be able to attend the meeting. I’ll be on holiday with my family. (since) 6. It was raining heavily. We decided to stay home and watch TV. (as) 7. He wants to get fit. He’s training hard. (because) 8. Sally was ill. She didn’t go to school yesterday. (since)
hoàn thành chuỗi PUHH sau và ghi rõ đk nếu có : Na------>Na2O----->NaOH------>Na2CO3--------->NaCl------->NaOH-------->NaHCO3
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