a) A={x∈N ∣ 10<x<16} b) B={x∈N∣ 10≤X ≤20} C) C={x∈N∣ 5<X ≤20} D) D={x∈N ∣ 10<X ≤100} E) E={x∈N ∣ 2982<x<2987} f) F={X ∈N*∣ x<10} g)G={X ∈N*∣X ≤ 4} h)H={X ∈N*∣X ≤ 100}

Phân tích thành nhân tử a) x ² - 2x - 4y ² - 4y b) x^4 + 2x ³ - 4x - 4

mình con tần này điểm thôi mong mng giúp vs ạ Exercise 21 : Mark the letter A, B, C or D to indicate the correct answer to each of the following questions. Question 1 : She_____the letter a few moments before my call came through. A. has just opened B. had just opened C. just opened D. just opens Question 2 : As soon as the boys_____the hall they_____to speak about books and writers. A. entered/begun B. were entering/began C. entered/began D. had entered/beganQuestion 3 : While we_____dinner at a restaurant someone came to the house and _____this note. A. had had/ left B. were having/left C. had/left D. were having/had left Question 4 : By the end of this year we_____a new house. A. will buy B. will be buying C. will have bought D. had bought Question 5 : “You always_____mistakes, you need_____the instructions more carefully.” A. make/read B. are always making/read C. make/to read D. are always making/to read Question 6 : Those students who_____the exam are going to take another one held in August. A. have failed B. failed C. had failed D. were failing Question 7 : I_____your brother this afternoon at Green Street. A. met B. had met C. was meeting D. have met Question 8 : She said she met you once at the Hilton last year._____since then? A. Have you met her B. Did you meet her C. Were you met her D. Had you met her Question 9 : Mr. Edwards_____history for 35 years, and is retiring soon. A. teaches B. is teaching C. taught D. has been teaching Question 10 : I’m tired. I_____the house since 9 this morning. A. am cleaning B. was cleaning C. had been cleaning D. have been cleaning Question 11 : I can’t believe that you_____all the three exercises. You just started five minutes ago. A. have finished B. have been finishing C. finished D. are finishing Question 12 : “How’s Peter doing?” “I don’t know. I_____from him for months.” A. have to hear B. haven’t heard C. didn’t hear D. don’t hear Question 13 : Their children_____lots of new friends since they_____to that town. A. have made - moved B. were making - have moved C. made - are moving D. made - have been moving Question 14 : He_____a cigarette and_____to the window. A. lighted/walked B. lit/was walking C. was lighted/was walking D. lit/had walked Question 15 : "You_____here before?" "Yes, I_____my holidays here last year. A. Were/spent B. Have you been/spent C. Were/had spent D. Have you been/have spent Question 16 : "You have just missed the last train." "Never mind, I_____."A. will walk B. was walking C. am walking D. am going to walk Question 17 : I_____my sister in April as planned. A. have seen B. will see C. am going to see D. see Question 18 : Then about a year ago, he_____and I_____from him since. A. has disappeared/haven’t never heard B. has disappeared/never heard C. disappeared/ have never heard D. was disappeared/had never heard Question 19 : After the guests_____she went back into the living-room and _____off the light. A. left/switched B. had left/switched C. had left/had switched D. had left/was switching Question 20 : When Alice gets here, you_____her to her room? A. will you show B. did you show C. have you shown D. are you showing Question 21 : As Hugh and I_____down the steps we nearly_____into my father. A. came/ran B. were coming/ran C. had come/ran D. came/were running Question 22 : If you want to see us, come to Tom's on Sunday. We_____for you there at midday. A. will wait B. will be waiting C. will have waited D. will have been waiting Question 23 : Come in, please. I_____for you long. A. have waited B. had waited C. have been waiting D. waited Question 24 : For a moment after their son_____the room, Mr and Mrs Smith merely_____and_____at each other. A. had left/had stood/looked B. had left/stood/looked C. left/stood/looked D. had left/had stood/had looked Question 25 : When we_____in London tonight, it_____. A. arrived/was probably raining B. arrive/ will be probably raining C. arrived/had been probably raining D. arrive/ will have probably rained Question 26 : I'm afraid I must ask you both what_____yesterday at 10:20 p.m. A. did you do B. had you done C. you were doing D. were you doing Question 27 : There_____great changes in our village in the past few years. A. have been B. had been C. was D. has been Question 28 : The noise from the trains_____me terribly last night. A. was annoyed B. annoyed C. has annoyed D. had annoyed Question 29 : Listen to this! I think this news_____you. A. surprises B. will surprise C. surprised D. would surprise Question 30 : By the end of this month, I hope I_____200 pages of my new novel.A. had written B. will have written C. will have been writing D. have written

Bài 5: Sử dụng từ trong ngoặc cho đúng thì và hãy trả lời những câu hỏi dưới: Yesterday (be).......... Sunday, Nam (get)...............up at six. He (do) ........... his morning exercises. He (take) ...............a shower, (comb).............. hair, and then he (have) .............. breakfast with his parents. Nam (eat)............ a bowl of noodles and (drink) a glass of milk for his breakfast. After breakfast, he (help) .............. Mom clean the table. After that, he (brush).......... his teeth, (put).......... on clean clothes, and (go)............ to his grandparents' house. He (have) .............. lunch with his grandparents. He (return) to his house at three o'lock. He (do).............. his homework. He (eat).......... dinner at 6. 30. After dinner, his parents (take).......... him to the movie theater. It (be)...............a very interesting film. They (come) .............. back home at 9. 30. Nam (go)................... to bed at ten o'clock. 1. What day was yesterday? ................................................................................. 2. What time did Nam get up? .............................................................................. 3. What did he do after breakfast? ......................................................................... 4. Who did he have lunch with? ........................................................................... 5. What time did he have dinner? .......................................................................... 6. What time did Nam go to bed? ........................................................................

Cho tam giác ABC vuông tại A (AB < AC). Biết góc B = 50° a, Tính số đo góc C b, Tia phân giác của góc B cắt cạnh AC tại D.Trên cạnh BC lấy điểm E sao cho BE=BA Chứng minh:∆ABD=∆EBD c, Chứng minh:DE ⊥BC d, Gọi K là giao điểm của 2 đường thẳng AB và DE.Chứng minh:DK=DC và AK=EC e, Chứng minh: BD ⊥ CK vẽ hình giúp mik nha

Phân tích đa thức thành nhân tử, ai ko tự tin làm thì né ra hộ

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