Đáp án:
$x + ( 2x + 3 ) = 42 - x$
$⇔x+2x+3=42-x$
$⇔x+2x+x=42-3$
$⇔4x=39$
$⇔x=\dfrac{39}{4}$
Vậy $x=\dfrac{39}{4}$
$x=\dfrac{39}{4}$
Giải thích các bước giải:
$x+2x+3-42+x=0$
$4x-39=0$
$4x=39$
Choose the correct answer. 11. I look forward to _____ you soon. A. see B. seeing C. seen D. saw 12. It’s a nice place for _____ who love nature and quietness. A. this B. that C. those D. the other 13. You like history, so Viet Nam National Museum of History is a _____ place. A. must-see B. must-be seen C. must-be seeing D. to see 14. The artisan ______ this statue in bronze. A. moulded B. cast C. carved D. knitted 15. The artisans in my village can live _____ basket weaving. A. for B. on C. up D.in 16. There is a big _____of handicrafts made by di¬fferent craftvillages. A. collect B. collection C. collector D.collecting 17. Last week we had a memorable trip to a new zoo on the ______ of the city. A. outskirts B. middle C. centre D.mid 18. Then we had a delicious lunch ______ by Nga and Phuong. A. prepare B. to prepare C. prepared D.preparing 19. I invited her to join our trip to Trang An, but she ______ downmy invitation. A. passed B. sat C. turned D.closed 20. We have to try harder so that our handicrafts can keep _____ theirs. A. on B. up C. up with D.up down
Bài 12: Một gen có tích giữa 2 loại nuclêôtit không bổ sung nhau là 5,25% số nuclêôtit của gen, trên một mạch đơn của gen có G=20% số nuclêôtit của mạch. Biết A>G và gen phiên mã tạo ra phân tử ARN thông tin (mARN) có X=U+G và A= 720 nuclêôtit. Tính số nuclêtit mỗi loại trên mỗi mạch đơn của gen và số nuclêôtit mỗi loại trên mARN.
Câu 11. Cho 6 điểm A, B, C, D, E, F trong đó không có ba điểm nào thẳng hàng. Vẽ đường thẳng đi qua các cặp điểm. Hỏi vẽ được bao nhiêu đường thẳng? A. 15 B. 10 C. 20 D. 16
Làm như thế nào hãy giải giúp tôi với
Giúp mình bài này với mọi người, thankss ạ
Làm gìum em câu 75 với ạ. GIẢI THEO CÁCH THÔNG THƯỜNG Ạ.KHÔNG giải theo cách QUY ĐỔI Ạ.
Calli chán NL ai vào chơi với tui
.....................................................................
3. When I rang Tessa some time last week, she said she was busy ______ that day. A. that B. the C. then D. this 14. I wonder _____ the tickets are on sale yet. A. what B. when C. where D. whether 15. Mathew _____ Emma that her train was about to leave. A. has reminded B. has reminded that C. reminded D. reminded that 16. Hello, Jim. I didn’t expect to see you today. Sophie said you _____ ill. A. are B. were C. was D. should be 17. Ann ______ and left. A. said goodbye to me B. says goodbye to me C. tell me goodbye D. told me goodbye 18. I told you ______ to switch off the computer, didn’t I ? A. don’t B. not C. not to D. to not 19. Bill was slow, so I ________ hurry up. A. tell him B. told him for C. told to D. told him to 20. “Could you tell me how to get to the airport?” A. he asked me how to get to the airport B. he said if I could tell him the airport C. he told me how to get to the airport D. he asked me to tell how to get to the airport 21. “Have you heard of her marriage?” A. she asked me if I hear of their marriage B. she asked me whether I had heard of their marriage C. she asked me if I had heard of their marriage D. B and C 22. Cindy said that “I haven’t seen John since last month.” A. Cindy said she hasn’t seen John since the previous month B. Cindy said she hadn’t seen John since the previous month C. Cindy said she wasn’t seen John since the previous month D. Cindy said she doesn’t see John since the previous month 23. The little boy said “two and two make four.” A.The little boy said that two and two made four. B.The little boy said that two and two have made four. C.The little boy said that two and two had made four. D.The little boy said that two and two make four. 24. “If I were you, I would go to the doctor. ”Minh said to Lan. A. Minh told Lan to become a doctor B. Minh advised Lan to go to the doctor C. Minh told Lan that he would to go to the doctor D. Minh advised Lan not to go to the doctor 25. His wife said to him: “write to me as often as you can” A. His wife told him to write to her as often as he can B. His wife told him to write to her as often as he could C. His wife told him writing to her as often as he could D. His wife told him writing to her as often as he can 26. “What were you doing last night, Mr John?” asked the police. A. The police asked what were you doing last night, Mr John B. The police asked Mr John what he had been doing the night before C. The police asked Mr John what he had been done the night before D. The police asked Mr John what had he been done the night before 27. The teacher advised us . A. to be careful when doing these exercises B. be careful when doing these exercises C. careful when doing these exercises D. are careful when doing these exercises 28. She told me . A. think well before I answered B. think well before I answer C. to think well before I answered D. think well before I will answer 29. He begged them --------------. A. help him B. should help him C. to help him D. help to him
Cho tam giác ABC Gọi D,E,F theo thứ tự là trung điểm BC, AC, AB qua F Vẽ đường thẳng d song song với BE cắt DE tại H . C/M a, Tứ giác BEHF là hình bình hành b, AD=CH c, AD , BH và EF đồng quy
Loga.vn - Cộng Đồng Luyện Thi Trực Tuyến