Cho a,b,c khác 0 và thỏa mãn: 2ab+1 trên 2b=2bc+1 trên c=ac+1 trên a CMR:a=2b=c hoặc 4a^2.b^2.c^2=1

Chứng minh rằng nếu a + b + c = 0 thì:A=[(a-b)/c+(b-c)/a+(c-a)/b][c/(a-b)+a/(b-c)+b/(c-a)] mk cần gấp

Một hỗn hợp gồm O2,O3 ở đktc có tỉ khối đối với hiđrô là 20,8 thành phần phần phân trăm của O3 trong hỗn hợp sẽ là?

Giúp mik với các bạn trả lời chỉ cần : Câu 1 . A hay B,C,D được rồi

Tính diện tích phần tô đậm ở hình bên, M biết nửa hình tròn tâm 0 đường kính AB nằm trong hình chữ nhật AMNB có NB = 4cm. các bạn giúp mk với.mik cảm ơn

Complete the sentences, using although, despite, in spite of, however, nevertheless. Sometimes, two answers are possible. 1. ________________ it was raining heavily, he went out without a raincoat. 2. My father is very busy. ________________, he is always willing to give a hand with the housework. 3. Some English words have the same pronunciation ________________ they are spelled differently, for example, dear and deer. 4. I was cold and wet. ____________________, Bob put on his swimming suit and went to the beach. 5. I think I did OK in my speech last night ________________ I’d had almost no sleep for 24 hours. 6. Carol arrived at the meeting _______________ I asked her not to be there. 7. The sky was grey and cloudy. _________________, we went to the beach. 8. It looks like they’re going to succeed _______________ their present difficulties. 9. _________________ there was no electricity, I was able to read because I had a candle. 10._________________ I heard the telephone ring, I didn’t answer it.

I. Choose the correct answer (A, B, C or D) (2ms) 1. There isn’t……………….rice left,so I have to go to the supermarket. A. some B. a C. any D. little 2. To make cakes you need some………………., sugar and eggs as well. A. flowers B. flour C. beer D. wine 3. ……………….potatoes do you need to make chips? A. How much B. How far C. How many D. How long 4. Emperor Ly Nhan Tong is the person who constructed ………………… A. The Imperial Academy B. Great Wall C. One-pillar Pagoda D. Ha Long Bay 5. Thien Quang Tinh well was ………………… as a world heritage. A. met B. recognized C. seen D. watched 6. Doctors’ stone tablets were made of ………………… A. sand B. brick C. stone D. cement 7. Stone tablets were erected on the ………………… of the tortoise after each Royal examination. A. back B. stomach C. head D. arm 8. Drivers have to ……………… your seatbelt whenever they drive. A. tie B. fasten C. put on D. put 9. ………………is it from your house to the nearest bus stop?” - “About 50 metres”. A. How much B. How long C. How far D. How often 10. Public ……………… in my town is good and cheap. A. travel B. journey C. tour D. transport giupw mik vs

giúp mình với ạ,mình cảm ơn nhiều

Ai giải hộ e với ạ mời các thần đồng

-làm giúp mình 2 câu địa lý với ạ