Đáp án:
$M = 6$
Giải thích các bước giải:
$2^{2x + 3} - 33.2^x + 4 = 0$
$\Leftrightarrow 8.(2^x)^2 - 33.2^x + 4 = 0$
$\Leftrightarrow \left[\begin{array}{l}2^x = 4 = 2^2\\2^x = \dfrac{1}{8} = 2^{-3}\end{array}\right.$
$\Leftrightarrow \left[\begin{array}{l}x = 2\\x = -3\end{array}\right.$
Do $a = x \in \Bbb Z^+$
$\Rightarrow a = 2$
Ta được: $M = 2^2 + 3^2 - 7 = 6$
Đặt $t=2^x$ $(t>0)$, ta có:
$8t^2-33t+4=0$
$↔ \left[ \begin{array}{l}t=4\\t=\dfrac{1}{8}\end{array} \right.$
$→ \left[ \begin{array}{l}2^x=4\\2^x=\dfrac{1}{8}\end{array} \right.$
$→ \left[ \begin{array}{l}x=2\\x=-3\end{array} \right.$
$→ a=2$
$→ M=2^2+3^2-7=6$
6. Tính giá trị biểu thức x³ + 3xy + y³ biết x+y = 1
đặt 2 câu với từ make a difference, mural
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phân tích đa thức thành nhân tử( DÙNG PP BỔ SUNG HẰNG ĐẲNG THỨC) a) 4x^2-7x-2 B) 4x^2+5x-6 C) 4x^2+15x+9 D) 2x^2- 3x-2 Giúp mình nha, dùng pp bổ sung hằng đẳng thức giúp mình !! Cảm ơn nhiều !
4. Tình các cặp số (x , y ) ; x , y ∈ z thỏa mãn đẳng thức a) x + y = xy b) 5xy - 2y² - 2x² = -2
chứng minh với mọi số nguyên n thì : a) ( $n^{2}$ + 3n - 1 ) ( n + 2 ) - $n^{3}$ + 2 chia hết cho 5 b) ( 6n + 1 ) ( n + 5 ) - ( 3n + 5 ) ( 2n - 1 ) chia hết cho 2
Bài 4: Điền giới từ thích hợp 24. He is the president ...................... our club. 25. She spends most ...............the time ............. the couch .......... front ....... the TV. 26. What do you usually do ............. school? 27. Why don't you come ............. .? 28. They swap cards .......... their friends. 29. Will you play a game ................ . catch? 30. What do you do ................ . recess? 31. They usually have portable CD player ................ small earphones. 32. I'll take part................ your club. 33. They read or study ............. the same time. 34. We enjoy all ..................... our classes. 35. ............. school we study many things. 36. ............. . history, we study past and present events.......... . Vietnam and .........the world. 37. ............. . physics, we learn ............how things work. 38. She learns how to use a computer .......... . her Computer Science class. 39. Newspapers are .......... the racks ................ the middle. 40. Math books are ................ . the shelves .......... . the left. 41. The largest library is ..................Washington D. C, the capital .......... the USA. 42. Those books .......... the back ............the libraries are .........English. 43. Now, come and look ...............the kitchen. 44. My uncle is ............. . work now. 45. Can I see the rest .........the house? 46. She'll have a party .......... . her birthday.
Câu 4: Trong tất cả những nhân vật em đã học, em thích nhân vật nào nhất? Hãy viết một đoạn văn từ 7 đến 10 câu nêu cảm nhận của em về nhân vật ấy. Câu 5: Theo em, trong đoạn trích Bài học đường đời đầu tiên, chi tiết nào là chi tiết quan trọng nhất? Vì sao? Câu 6: Chi tiết nào làm em ấn tượng nhất trong truyện ngắn Bức tranh của em gái tôi. Hãy viết đoạn văn từ 7 đến 10 câu nêu cảm nhận của em về chi tiết ấy. Câu 7: Tìm đọc một truyện ngắn (ngoài SGK) mà em yêu thích, nêu cảm nhận về chi tiết hoặc nhân vật mà em yêu thích nhất
Bài 4: Điền giới từ thích hợp 1. Lan'll have a party ...................... Friday evening. 2. Would you like to come .......... my house ............lunch? 3. She takes care ............. her family. 4. She works .........a local supermarket. 5. My mother works...............the field............. my father. 6. Does your father work ............. . Hanoi? 7. David is good ................... . Math. 8. What do you do ............. your free time? 9. Are you interested ............. . sports?. 10. There's a good film ............. . ......... the moment. 11. Thanks .......... . your letter. 12. I'll see my mom and dad ................ . their farm. 13. We have to work hard .......... home and................ school 14. We'll visit her .......... Christmas. 15. Are you tired ............. . watching TV? 16. She often brings them ............... school. 17. He works .......... a factory. 18. We always go to Ha Long Bay .......... vacation. 19. Tell me more .......... . your family. 20. Can you send me a photo .......... . your family? 21. He goes .......... the city ............his wife. 22. It takes 18 hours to get .........Hanoi .......... coach. 23. We write .......... each other twice a week.
Bài 3: Chia động từ cho đúng 1. In all the world, there (be) __________ only 14 mountains that (reach) __________above 8,000 meters. 2. He sometimes (come) __________ to see his parents. 3. When I (come) __________, she (leave) __________for Dalat ten minutes ago. 4. My grandfather never (fly) __________ in an airplane, and he has no intention of ever doing so. 5. We just (decide) __________ that we (undertake) ____________ the job. 6. He told me that he (take) __________ a trip to California the following week. 7. I knew that this road (be) __________ too narrow. 8. Right now I (attend) __________ class. Yesterday at this time I (attend) __________class. 9. Tomorrow I'm going to leave for home. When I (arrive) __________at the airport, Mary (wait) __________ for me. 10. Margaret was born in 1950. By last year, she (live) __________on this earth for 55 years. 11. The traffic was very heavy. By the time I (get) __________to Mary's party, everyone already (arrive) __________ 12. I will graduate in June. I (see) __________ you in July. By the time I (see) __________ you, I (graduate) __________. 13. I (visit) __________ my uncle's home regularly when I (be) __________ a child. 14. That book (be) __________ on the table for weeks. You (not read) __________ it yet? 15. David (wash) __________ his hands. He just (repair) __________ the TV set. 16. You (be) __________here before? Yes, I (spend) __________ my holidays here last year. 17. We never (meet) __________ him. We don't know what he (look) __________ like. 18. The car (be) __________ ready for him by the time he (come) __________tomorrow. 19. On arriving at home I (find) __________that she just (leave) __________a few minutes before. 20. When we (arrive) __________ in London tonight, it probably (rain) __________. 21. It (rain) __________ hard. We can't do anything until it (stop) __________ 22. Last night we (watch) __________TV when the power (fail) __________. 23. That evening we (stay) __________up to talk about the town where he (live) __________for some years. 24. I (sit) __________down for a rest while the shoes (repair) __________. 25. Half way to the office Paul (turn) __________round and (go) __________back home because he (forget) __________to turn the gas off. 26. London (change) __________a lot since we first (come) __________ to live here. 27. While we (talk) __________on the phone the children (start) __________fighting and (break) __________a window 28. He used to talk to us for hours about all the interesting things he (do) __________ in his life. 29. You know she (stand) __________looking at that picture for the last twenty minutes. 30. I (spend) __________ a lot of time travelling since I (get) __________this new job. 31. When we (be) __________ at school we all (study) __________Latin. 32. When I (meet) __________ him, he (work) __________as a waiter for a year. 33. After he (finish) __________ breakfast he (sit) __________down to write some letters. 34. She (have) __________a hard life, but she's always smiling. 35. I think Jim (be) __________ out of town.
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