Tính giá trị biểu thức:A=3x^2-3xy+2y^2 với |x|=1;|y|=3

Các câu hỏi liên quan

LUYỆN TẬP CAU WISH:10. I speak English terriblely. I wish I English as fluently as you. A. spoke B. speak C. had spoken D. will speak 11. My house is too small and old. I wish I a bigger one. A. have B. will have C. had had D. had 12.Sophie wishes her father here now to help her. A. has been B. is being C. is D. were 13.I love California. I wish I go there right now. A. can B. went C. could D. may 14. Iris is always moaning about others. I wish she . A. know how I am upset B. knew how I am upset C. will know how I am upset D. knows how I am upset 15.Stella hates having red hair. She wishes she blonde hair. A. have B. will have C. had D. had had 16.They wish they the exam. A. pass B. passed C. will pass D. are passing 17.Diego is driving too fast. I wish he more slowly. A. drive B. drove C. were driving D. will drive 18. It’s a pity I didn’t take my doctor’s advice. -I wish you __________ the doctor's advice. A. took B. would take C. had taken D. could take 19. I hate having red hair. I wish I ______ blonde hair. A. had B. would have C. had had D. am having 20. This exercise is very boring. I wish the teacher ______ us some more interesting things to do. A. gave B. would give C. had given D. will give 21. I wish I__________ a doctor in the future. A. am B. were C. had been D. would be 22. I wish that some day I ___________ able to marry her. A. will be B. am C. would be D. had been 23. I wish I_________ enough money to buy the house. A. had B. have C. had had D. would have 24. John wishes he ________ a scientist when he grows up. A. is B. was C. will be D. would be 25. I'm not very fit. I wish ______ A. I would be fitter B. I were fitter C. I was fitter D. I am fitter 26. It's very hot. A. I wish it were cooler. C. I wish it were hotter. B. I wish it was rain tomorrow. D. If only it had rained. 27. He likes to swim. ->He wishes he ……………… near the sea. A. lived B. living C. lives D. to live 28. She wishes she ……………. blue eyes. A.has B. had C. had had D. would have 29. If only I ___ him now. A. see B. saw C. have seen D. seen 30. I wish it ___ a holiday today. A. were B. will be C. is D. had been 31. What a pity I didn’t meet you yesterday. A. If only I met you yesterday. B. If only I meet you yesterday. C. If only I had met you yesterday. D. If only I hadn’t met you yesterday. 32. Those children are really noisy. A. I wish they were quieter B. I wish they would be quiet C. If only they were quieter D. Both A and C are correct 33. I wish I …….................... help you. A. would B. can C. could D. will 34. She wishes she ……………………. him yesterday. A. would meet B. meets C. met D. had met 35. If only my motorbike…broken down again, I would have arrived on time A.would B. hadn’t C. didn’t D. wasn’t 36. I wish I _________ in prison, but I am A. wasn't B. am not C. weren't D. were 37. I wish you…………….make that noise, it’s annoying! A. don't B. wouldn't C. would D. couldn't 38. I hate Canadian winters. I wish I ______ in Hawai right now. A. was B. am C. will be D. were 39. You talk more than you work. The teacher wishes that __________. A. you work more than you talk B. you worked more than you talked C. you worked more than you talk D. you had worked more than you had talked 40. Susan regretted not buying that villa. A. Susan wished she had bought that villa. B. Susan wished she bought that villa. C. Susan wished she could buy that villa. D. Susan wished she hadn’t bought that villa. lm hộ mik vs

Cho 11,5g hỗn hợp gồm ACO 3 , B 2 CO 3 , R 2 CO 3 tan hết trong dung dịch H 2 SO 4 thu được 2,24 lít CO 2 (đktc). Khối lượng muối sunfat tạo thành là A. 16,7 gam. B. 14,6 gam. C. 15,1 gam. D. 12,5 gam. Bài 14: Hoà tan hoàn toàn 19,2 hỗn hợp gồm CaCO 3 và MgCO 3 trong dung dịch H 2 SO 4 dư thấy thoát ra V (lít) CO 2 (đktc) và dung dịch có chứa 26,4 gam hỗn hợp muối. Xác định V. A. V = 3,36 lít C. V = 8,96lít C. V = 4,48 lít D. V = 5,6 lít Câu 15: Hoà tan hết m gam hỗn hợp gồm M 2 CO 3 và RCO 3 trong dung dịch HCl dư thu được dung dịch Y và V lít khí CO 2 (đktc). Cô cạn dung dịch Y thì được (m + 3,3) gam muối khan. Giá trị của V là A. 2,24. B. 3,36. D. 4,48. D. 6,72. Câu 16: Hòa tan hoàn toàn 20,6 gam hỗn hợp gồm Na 2 CO 3 và CaCO 3 bằng dung dịch HCl dư, thu được V lít khí CO 2 (đktc) và dung dịch chứa 22,8 gam hỗn hợp muối. Giá trị của V là A. 1,79. B. 4,48. C. 2,24. D. 5,60. Câu 17: Cho 2,13 gam hỗn hợp X gồm ba kim loại Mg, Cu và Al ở dạng bột tác dụng hoàn toàn với oxi thu được hỗn hợp Y gồm các oxit có khối lượng 3,33 gam. Tính thể tích dung dịch HCl 2M vừa đủ để phản ứng hết với Y là A. 150 ml. B. 75 ml. C. 750 ml. D. 156 ml. Câu 18: Cho 17,4 gam hỗn hợp X gồm ba kim loại Mg, Zn và Al ở dạng bột tác dụng hoàn toàn với oxi thu được hỗn hợp Y gồm các oxit có khối lượng 25,8 gam. Để hòa tan hết Y cần dùng 500 ml dung dịch H 2 SO 4 a (mol/l). Giá trị của a là A. 1,0. B. 1,1. C. 1,05. D. 1,2.

1. The boys broke a window when they football. A. played B. were playing C. half played D. are playing 2. I about him when suddenly he came in. A. talk B. talked C. am talking D. was talking 3. Last night at this time, they the same thing. She _ and he the newspaper. A. are doing/is cooking/is reading B. were doing/was cooking/was reading C. was doing/has cooked/is reading D. had done/was cooking/read 4. When Carol last night, I my favorite show on television. A. was calling/watched B. called/have watched C. called/was watching D. had called/watched 5. When I home last night, I that Jane a beautiful candle light dinner. A. had arrived/discovered/preparing B. was arriving/has discovered/was preparing C. have arrived/was discovering/had prepared D. arrived/discovered/was preparing 6. While I TV last night, a mouse ran across the floor. A. watch B. watched C. was watching D. am watching 7. When it began to rain, they in the yard. A. played B. had played C. were playing D. have played 8. When I woke up this morning, it A. rained B. was raining C. has rained D. is raining 9. While Tom tennis, Ann a shower. A. played/took B. playing/taking C. was playing/was taking D. was play/was take 10. When they in the garden, the phone . A. worked/was ringing B. were working/rang C. worked/rang D. work/rings 11. They tea when the doorbell . A. have/is ringing B. were having/rang C. had had/ rang D. having/ringing 12. Father his pipe while mother a magazine. A. smoked/read C. had smoked/read B. was smoking/was reading D. smoking/reading 13. When I into the office, my boss for me. A. came/was waiting B. was coming/waited C. had come/waited D. came/waiting 14. When I John, he across the road. A. see/ walks B. see/was walking C. saw/was walking D. saw/is walking 15. When he , we _ dinner. A. arrived/having B. arrived/were having C. was arriving/had D. had arrived/had 16. While they chess, we the shopping. A. playing/doing B. were playing/doing C. played/did D. were playing/were doing 17. They football when the lights in the stadium out. A. were playing/went B. played/was going C. were playing/ was going D. playing/went 18. While George and John their room, she the ironing. A. cleaning/doing B. were cleaning/was doing C. were cleaning/doing D. cleaning/was doing 19. While I TV last night, a mouse ran across the floor. A. watch B. watched C. was watching D. am watching 20. While George and John their room, she the ironing. A. cleaning/doing B. were cleaning/was doing C. were cleaning/doing D. cleaning/was doing Giải giúp mình gấp ạ ! mình cảm ơn trước ạ