giup mk , 8h 30 mk phai nop roi

cho tam giác ABC có diện tích S,trung tuyến AM. Gọi N là trung điểm AM ,BN cắt AC tại E,CN cắt AB tại F. Kẻ MK song song CF. Tính diện tích AFNE theo S

a+b+1/2>=√a + √b a,b là số thực

Nêu và giải thích những lợi ích của bò sát đối với đời sống con người ?

cho 2 điểm A(3,-4),B(7,6),tọa độ trung điểm của AB là cặp số nào?

Tìm tất cả các số nguyên a biết: (6a +1) chia hết cho ( 3a -1)

Một dung dịch axit HCl 45% và một dung dịch HCl 15%. Để có 1 dd mới có nồng độ 20% thì cần phải pha chế về khối lượng giữa 2 dd theo tỉ lệ là bao nhiêu?

Choose the underlined part among A, B, C or D that needs correcting. 1) In my opinion that girl is enough beautiful to be a movie star. 2) The specific gravity of the water in the great Salt Lake is too great that one cannot sink or completely submerge in it. 3) This lesson is such long that I have written it for 30 minutes. 4) The pull of the earth is too strong that no one can jump as high as three meters. 5) It was so an interesting film that my mother had seen it three times. 6) Mary is so an intelligent pupil that she can answer this question. 7) Mars is far so from the earth that our spaceships cannot reach it in a few months. 8) Despite the time of the year, yesterday’s temperature was enough hot to turn on the air conditioning. 9) I was such nervous that I didn’t think I would pass the exams. 10) The problems of pollution are too difficult for us to solving. 11) His father was so poor to send him to school. 12) This refrigerator is very old to keep things at a proper temperature. 13) She is such good at mathematics that everyone admires her. 14) George is not enough intelligent to pass this mathematics class. 15) The novel was such interesting that I had read it all night. 16) He was tired that he couldn’t continue his work. 17) It was so a funny film that I burst out laughing. 18) His TOEFL score was enough high to be accepted. 19) It was so an exciting novel that I do not want to stop reading it. 20) The woman was too old that she could not run.

Bài 1. Một người kéo một hòm gỗ trượt trên sàn nhà bằng dây có phương hợp góc 450 với phương ngang. Lực tác dụng lên dây bằng 120N.Tính công của lực đó khi hòm trượt đi được 25m.

$\frac{2-x}{2001}$ - 1 = $\frac{1-x}{2002}$ - $\frac{x}{2003}$ Giải phương trình trên (Cảm ơn nha)