Giả sử x∈Q . Kí hiệu [x] , đọc là phần nguyên của x , là số nguyên lớn nhất không vượt quá x, nghĩa là [x] là số nguyên sao cho [x]≤x<[x] +1 Tìm [2,3], [$\frac{1}{2}$ ],[-4],[-5,16]

Cân bằng : `X + H_2O → X(OH)_y + H_2`

31. By the time he arrives here tomorrow, they _______ for London. A. would have left B. will have left C. will left D. are leaving 32. When I _______ to the airport, I realized that I _______ my passport at home. A. got/had left B. got/left C. had got/had left D. got/was left 33. Call me as soon as you _______ your test results. A. get B. will get C. will have got D. got 34. I _______ along the street when I suddenly heard footsteps behind me. A. was walking B. am walking C. walk D. walked 35. The boy fell while he _______ down the stairs. A. run B. running C. was running D. runs 36. Iwill come and see you before I _______ for America. A. leave B. will leave C. have left D. left 37. She hurt herself while she _______ hide-and-seek with her friends. A. is playing B. had played C. played D. was playing 38. Only after the bus _______ for a few miles did Jane realize she was on the wrong route. A. was running B. had run C. has run D. runs 39. While I _______ at the bus stop, three buses went by in the opposite direction. A. was waiting B. waited C. had waited D. were waiting 40. By the end of last March, I _______ English for five years. A. had been studied B. had been studying C. will have been studying D. will have studied 41. By the end of next March, I _______ English for five years. A. had been studied B. had been studying C. will have been studying D. will have studied 42. Linda took great photos of butterflies while she _______ in the forest. A. was hiking B. is hiking C. hiked D. had hiked 43. When I _______ for my sister in front of the supermarket, a strange man cameto talk with me. A. was waiting B. waited C. had waited D. were waiting 44. When I came to visit her last night, she _______ a bath. A. is having B. was having C. has had D. had had 45. John _______ in the same house since he left school. A. lived B. had lived C. was living D. has lived 46. He will take the dog out for a walk as soon as he _______ dinner. A. finish B. has finished C. will finish D. finished 47. The phone _______ suddenly while Joanna was doing the housework. A. rang B. was ringing C. had rung D. is ringing 48. A fire-fighter was injuried severely while he _______ to put out a fire. A. would help B. helped C. has helped D. was helping 49. By the time I came here all the better jobs _______ taken. A. have been B. were C. are D. had been 50. While Peter _______ the rose bush in the back yard, the phone rang. A. had been watering B. watering C. watered D. was watering

cách để tìm số đo của góc nhọn khi biết tỉ số lượng giác của góc đó trên máy tính vinacal 570es plus II

Cho mình hỏi hoàn cảnh sáng tác của Nói với con là khi tác giả có đứa con gái đầu lòng (mới sinh ấy) hay là khi con gái ông được 1 tuổi vậy. Nhanh giúp mình không cần giải thích gì đâu đáp án thôi được rồi.

Câu 3 bài 2 và bài 3. Nhanh nhé, cảm ơn ạ

Giá trị của a để tổng bình phương hai nghiệm của phương trình x ²+ax+a-2=0 đạt giá trị nhỏ nhất

Làm giúp ạ . Cảm ơn giúp hộ mik

Ở người khi tình trạng đầu hói bị chi phối bởi gen nằm trên nhiễm sắc thể thường nhưng bị chi phối ảnh hưởng bởi gen giới tính gen là trội ở đàn ông nhưng lại ở đàn bà. Trong một cộng đồng có 10.000 người đàn ông ông có 7225 người không bị hói đầu. Vậy nếu 10.000 ngừơi đan bà thì số người không bị hói là?

Làm a,b,c không cần hình nha mình xem bài của mình thiếu ở đâu thôi