Giải thích vì sao các tỉnh phía Nam thường xuyên bị nhiễm phèn, nhiễm mặn? Hậu quả của việc nhiễm phèn, nhiễm mặn?

Cho tam giác ABC cân tại A, có góc A=50 độ. Trên đoạn thẳng BC lấy điểm D, trên tia đối của tia CB lấy điểm E sao cho BD=CE. Từ D kẻ đường vuông góc với BC cắt đường thẳng AB ở M, từ E kẻ đường vuông góc với BC cắt đường thẳng AC ở N. a, Tính góc B, góc C của tam giác ABC. b, Chứng minh: MD//NE và MD=NE. c, MN cắt DE ở I. Chứng minh I là trung điểm của DE. ( giúp mình với mình cần gấp, xin các bạn đấy )

XIV. Complete the sentences with present participle or past participle form of the verb in brackets. 1. The film wasn't as good as we had expected. (disappoint) a. The film was. b. We were ________________________ with the film. 2. Diana teaches young children. It's a very hard job but she enjoys it. (exhaust) a. She enjoys her job but it is often ______________________. b. At the end of a day's work, she is often _______________________. 3. It's been raining all day. I hate this weather. (depress) a. This weather is _____________________. b. This weather makes me ______________________. c. It's silly to get ____________________ because of the weather. 4. Clare is going to the United States next month. She has never been there before. (excite) a. It will be an ________________ experience for her. b. Going to new places is always ________________. c. She is really __________________ about going to the United States. XVII: Make one sentence from two. Use the word(s) in brackets in your sentences. 1 I couldn't sleep. I was very tired. Despite I couldn't sleep despite being very tired. 2. They have very little money. They are happy. In spite of ................................................................................................................................... 3. My foot was injured. I managed to walk to the nearest village. Although ..................................................................................................................................... 4. I enjoyed the film. The story was silly. In spite of ................................................................................................................................... 5. We live in the same street. We hardly ever see each other. Despite ...................................................................................................................................... 6. I got very wet in the rain. I was only out for five minutes. Even though .............................................................................................................................. XVIII. Rewrite sentences with In spite of / Despite /because / because of 1. Although Tom was a poor student, he studied very well. à In spite of _______________________________________________________________ 2. Mary could not go to school because she was sick. à Because of _______________________________________________________________ 3. Although the weather was bad, she went to school on time. à Despite _______________________________________________________________ 4. Because there was a big storm, I stayed at home. à Because of _______________________________________________________________ 5. In spite of his good salary, Tom gave up his job. àAlthough_______________________________________________________________ 6. He is so young. His acting is excellent. à Although________________________________________________________________ 7.The film poster is fascinating. I don't want to see this film. àIn spite of________________________________________________________________ 8.Although our plan is careful, we made some mistakes. àDespite_________________________________________________________________ làm hết mình cho 30 điểm, thật chính xác nha

Chứng minh rằng x²y⁴+2(x²+2)y² +4xy+x²>4xy³ với mọi x,y €R

lặn lội thân cò khi quãng vắng eo sèo mặt nước buổi đò đông thuộc kiểu ẩn dụ nào Hãy chỉ rõ

Bài 3: Tìm giá trị của m sao cho phương trình: a) 5(m + 3x)(x + 1) – 4(1 + 2x) = 80 có nghiệm x = 2. b) 3(2x + m)(3x + 2) – 2(3x + 1)2 = 43 có nghiệm x = 1. c) Phương trình: 2x + m = x – 1 có nghiệm x = – 2. d) Phương trình: (2x + 1)(9x + 2m) – 5(x + 2) = 40 có nghiệm x = 2

a. ( - 25 ) + 20 -12 b. - 24 + 18 + 34 - (-28 ) c. ( 1597 - 339 ) + ( - 1597 + 639 ) d. ( - 4) mũ 4 + ( - 3 ) ³ . ( -2 ) - ( - 146 + 4 mũ 4 )

lan có 12500 đồng , huệ có nhiều hơn lan 2900 đồng . hồng có ít hơn huệ 2500 đồng . hỏi trung bình mỗi bạn có bao nhiêu tiền ?

III.Put the correct form of verbs: 1.Mai (visit)_______________________ Nha Trang last summer. 2. You should (wash)_________________ your hands before meals. 3. Lan (visit)________________________Nha Rong Harbor next week. 4. They (play)__________________________ soccer in the school yard at the moment. 5.Nam (not be)_________ very sporty. He never (take)__________part in after school activities . 6.Be quiet! The baby (sleep)________________. You shouldn’t (make)___________ noise. 7. We (have)___________________ a day off next week. 8. Where (be)__________ your father now?- He (work)_______________________in the gadern. 9. Next week, I (see) __________________a movie. Let’s (go) ________________with us. 10. He can (speak)_________________ English well. 11.We (not go)__________________ to the movies so often. 12.Tomorrow is Sunday. What______you (do)_____________? - I (stay)_________________ at home . 13. The members of the stamp collector’s club (meet)_________________ at the library next Friday. 14.I’d like (see)_________________a movie tonight. 15.You should (relax)_____________________.

Cho tam giác abc cân tại a có góc a = 40 độ gọi h là trung điểm của bc a) tính góc b và chứng minh ah vuông góc với bc b) đường trung trực của đoạn ac cắt tia cb ở m tính góc mah c) trên tia đối của tia am lấy điểm n sao cho an=bm chứng minh am=cn d) vẽ ci vuông góc với mn tại i chứng minh i là trung điểm của mn