Ai làm giúo mình với mình cần gấp lắm. giải chi tiết ạ

Cho a,b,c thỏa mãn : 3ab(3a-b) + 3ac(3c-a) + 3bc (3b-c) = 26abc Chứng Minh tồn tại 1 số = 3 số kia

Chọn thì thích hợp nhất để hoàn thành các câu sau: 19. There ______________ no rule about the movement of traffic before the Pope came to visit Paris. A. has been B. was C. had been D. is 20. The King just ____________ here yesterday. A. had come B. comes C. has come D. came 21. While I ________________ along the road, I saw a friend of mine. A. cycled B. was cycling C. had cycled D. were cycling 22. It is the largest ship I______________ A. had seen B. saw C. have ever seen D. see 23. I ________________ ghost in my life. A. has never seen B. never saw C. had never seen D. have never seen 24. Mary ____________ an hour ago. A. phoned B. has phoned C. phones D. was phoning 25. The light went out while I _______________dinner. A. has B. was having C. am having D. had 26. This is the house that Jack ______ three years ago. A. was building B. builds C. had built D. built 27. He ___________ the effects of radiation when he suddenly died A. was studying B. studied C. had been studying D. has studied

Cho a tác dụng với CaCO3, KMnO4, CaC2, Al4C3, FeS thu được lần lượt các khí: CO2, Cl2, C2H2, CH4, H2S. Xác định a và viết PTrình PỨ trong các Thí nghiệm trên

GIUP TU CAU 1-7 40D CUA TOI DO GHI DAP SO NHANH NHA 9 H PHAI NOP

làm bài 3 hoặc 4 đều đc nha chọn 1 trong hai bài bạn nào dễ thương thì làm cả hai luôn cx đc

Dạ mọi ơi giải cho em mấy câu này giùm ạ , em cảm ơn

Giúp mình câu 7, 8, 9 nha. Vote 5⭐

change these sentences into interrogative and negative sentences - they ko to the church every sunday ............................................................... ................................................................ -she often watches tv in the evening ............................................................... ................................................................... -lan does hẻ homework in the evening .................................................................... .................................................................... -my mother has breakfast at 6.00 ......................................................................... .......................................................................... -i and my friend study english on monday ........................................................................ ......................................................................

Mọi người ơi giải thích kĩ hộ em chỗ dấu bằng xảy ra với. Em cảm ơn. Em đang cần gấp. Đề bài: Tìm minA= x^4 + y^4 + z^4 biết xy + yz + xz =1