cho a,b là số nguyên dương thỏa mãn: 3a^2+a=4b^2-b chứng minh a+b là số chính phương.

20 Mark the letter A, B, C, or D on your answer sheet to indicate the word(s) OPPOSITE in meaning to the underlined word(s) in each of the following questions. Question 16: We had better preserve cultural values of our country. A: change B: keep C: remember D: destroy 21 Choose the word whose stressed pattern is pronounced differently from the others. A: musician B: celebration C: librarian D: procession 22 Choose the word whose underlined part is pronounced differently from the others. A: performed B: prayed C: offered D: worshiped 23 Mark the letter A, B, C or D on your answer sheet to indicate the most suitable response to complete each of the following exchanges. Question 13. Tom: “Would you like to go to the Lim Festival with us? Peter: “_________.” A: Thanks. I’d love to B: It’s my pleasure C: Of course D: It’s all right 24 Choose the best answer A, B, C or D to complete the sentence. Question 7. In 2010, Hanoi, the capital of Viet Nam_______ its 1000th anniversary. A: worshipped B: remembered C: commemorated D: celebrated 25 Choose the best answer A, B, C or D to complete the sentence. Question 8. Tet is the most important festival in Viet Nam; _______, most Vietnamese return home for Tet. A: nevertheless B: so C: but D: therefore

Cho x, y, z là các số thực dương thỏa mãn x+2y+3z=11/2 chứng minh rằng 6(3xy+4xz+2zy)+6x+3y+4z+72xyz ≤ 107/8

Cần anh chị chuyên toán giúp em câu đạo hàm này với ạ

Một tế bào có kí hiệu bộ NST như sau : AABbDd Viết kí hiệu bộ NST sau giảm phân

Tìm nghiệm nguyên của phương trình: 2x + 5y – 3xy =1.

2. Alice is very young. She can’t stay at home alone. …………………………………………… 3. It’s very late. We can’t see a movie. …………………………………………………………… 4. She lives far from school. She can’t walk there. ……………………………………………… 5. It’s very cold. We can’t go swimming today. ………………………………………………… 6. The jacket is very small. He can’t wear it. ……………………………………………………… 7. Peter is very tired. He can’t study. ……………………………………………………………… 8. The pencil is very short. She can’t use it. ……………………………………………………… 9. The meeting is very important. We can’t miss it. ……………………………………………… 10. Sarah can’t take a day off. She was very busy. ………………………………………………… 11. You speak so fast that I can’t catch up with your words. …………………………………………………………………………………………………… 12. The piano was too heavy. We couldn’t hang it on the wall. …………………………………………………………………………………………………… 13. The test was very long. We can’t finish it in half an hour. …………………………………………………………………………………………………… 14. Mike was very busy. He couldn’t go to his aunt’s house warming party. …………………………………………………………………………………………………… 15. Some movies are very violent. Children shouldn’t watch them …………………………………………………………………………………………………… 16. He reached the station very late. He couldn’t catch the train. ……………………………………………………………………………………………………

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Đề phân tích đa thức thành nhân tử x^6 - y^6