Giúp mình với mình hứa sẽ đánh giá 5 sao chỉ cần làm ngắn gọn Nguyên tố R có ba đồng vị là X, Y và Z. Tổng số hạt cơ bản của ba đồng vị này là 129; trong đó, số hạt mang điện nhiều hơn hạt không mang điện là 39 đơn vị. Số notron của X nhiều hơn của Y 1 đơn vị. Trong Z, các loai cơ bản bằng nhau. Viết kí hiệu nguyên tử của X, Y và Z.

Cho hình chóp tứ giác đều có cạnh đáy bằng $a$ và cạnh bên bằng $b$. Khi đó thể tích của hình chóp bằng

Mark the letter A, B, C, or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions. Question 31. Meal time gives children a time to learn how some of their favorite dishes make. A. gives B. to learn C. how D. make Question 32. I had my motorbike repair yesterday but now it still doesn’t work. A. had B. repair C. but now D. work Question 33. If you are working with young children in a primary school, you will find that teaching lively songs and rhymes are very popular. A. with B. primary C. will find D. are Question 34. Paris has been well-known about its famous monuments, beautiful music, and wonderful restaurants for over 100 years. A. well-known B. about C. monuments D. for

giúp mình với ạ!! mình cần gấp!!

Giúp mình với mọi ng Nhớ tóm tắt + Lời giải nhé

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks Why is it that many teenagers have the energy to play computer games until late at night but can't find the energy to get out of bed (26) ________ for school? According to a new report, today's generation of children are in danger of getting so (27) ________ sleep that they are putting their mental and physical health at (28) ________. Adults can easily survive on seven to eight hours' sleep a night, (29) ________ teenagers require nine or ten hours. According to medical experts, one in five youngsters (30) ________ anything between two and five hours' sleep a night less than their parents did at their age. (By Tim Falla and Paul A. Davies, Solutions Advanced. OUP) Question 26. A. behind time B. about time C. in time D. at time Question 27. A. few B. less C. much D. little Question 28. A. jeopardy B. threat C. risk D. danger Question 29. A. or B. because C. whereas D. so Question 30. A. puts B. gets C. brings D. makes

Cho hình bình hành ABCD. Hãy phân tích vecto AD theo 2 vecto a = AC, b = BD

Cân bằng phương trình sau: Al+ NaOH+H2O--->NaAlO2+H2

Mark the letter A, B, C, or D on your answer sheet to indicate the most suitable response to complete each of the following exchanges. Question 19. Ann has just had dinner at Keren’s. - Ann: "Thank you for a wonderful evening." - Karen: "_____________." A. You're welcome B. Thanks a lot C. Have a good day D. Cheers Question 20. On discussing the problems with Peter in the office, Mary felt hot. - Mary: “It is very hot in here. ____________?” - Peter: “Of course.” A. Must you open the window B. Shall you open the window C. Could you open the window D. A or C

Mình cần gấp ạ .Mình cần cách giải thích ạ . Giải hộ mình với ạ