Cho đường tròn tâm (O) bán kính OA=6cm. Gọi H là trung điểm của OA, đường thẳng vuông góc với OA tại H cắt đường tròn (O) tại B và C. Kẻ tiếp tuyến với đường tròn (O) tại B cắt đường thẳng OA tại M. a) Tứ giác OBAC là hình gì ? V ì sao ? b) Tính độ dài BM Giúp với tớ đang cần gấp lắm

1/ 7; -12 ; +4 ; 0 ; │-8│; -10; -1 2/ -12; │+4│; -5 ; -3 ; +3 ; 0 ; │-5│ * giảm dần 3/ +9 ; -4 ; │-6│; 0 ; -│-5│; -(-12) 4/ -(-3) ; -(+2) ; │-1│; 0 ; +(-5) ; 4 ; │+7│; -8

các bạn ơi cho mình hỏi ghép cây là gì

: Tổng(hiệu ) sau có chia hết cho 3, cho 9 không? a) A =10^2018 – 1 b)B = 10^2019 + 2 c) C =10^n - 1 d) D = 10^n + 8

a) x+2/x-2 - 1/x =2/x(x-2) b) x+1/x-2 + x-1/x+2 = 2(x^2+2)/x^2-4 c) (2X+3)(3X+8/2-7X +1) = (X-5)(3X+8/2-7X +1)

hai vòi nc cùng chảy vào 1 bể sau 12h thì đầy bể,Nếu vòi I chảy 1 mk trong 3h rồi khóa lại rồi mwor vòi 2 chảy tiếp trong 18h thì cả 2 chảy đầy bể Hỏi mỗi vòi chảy 1 mk trong bao lâu thì đầy bể? Các bạn giúp mk nhanh nhé.Trước 5h30 mk phải nộp rùi

bài 5 hình dưới, yêu cầu lời giải đầy đủ và chi tiết

trong cac nguyen tac phong tru sau benh hai , nguyen tac nao quan trongj nhat ? vi sao?

1 Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits blank (20). Do you know about the history of Jeans? Jeans are very popular with (17)________people all over the world. Some people say that jeans are the “uniform” of youth. But they haven’t always been popular. The story of jeans (18)________almost two hundred years ago. People in Genoa, Italy made pants. The cloth made in Genoa was (19)________“jeanos”. The pants were called “jeans”. In 1850, a salesman in California began selling pants made of canvas. His name was Levi Strauss. Because they were so strong, “Levi’s pants” became (20)________with gold miners, farmers and cowboys. Six years later Levis began making his pants with blue cotton cloth called denim. Soon after, factory (21)________in the US and Europe began wearing jeans. A: famous B: good C: popular D: wonderful 2 Choose the correct sentence (A, B, C or D) made from the suggested words. Question 23. you/ know/ how much/ time/ he/ spend/ surf/ web/ a day? A: Do you know how much time he spends surfing the web a day? B: Do you know how much time does he spend surfing the web a day? C: Do you know how much time he spends to surf the web a day? D: Do you know how much time does he spend surfing web a day? 3 Choose the best answer A, B, C or D to complete the sentence. Question 8. He was the first man _______________ to help the flood victims. A: arrived B: arrive C: to arrive D: arriving 23 Choose the best answer A, B, C or D to complete the sentence. Question 7. Working hours will fall to under 35 weeks, __________________? A: will they B: won’t they C: will it D: won’t it 24 Choose the best answer A, B, C or D to complete the sentence. Question 11. Alexander Graham Bell was a great___________, who invented the telephone. A: conservationist B: scientist C: developer D: explorer 25 Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits blank (21). Do you know about the history of Jeans? Jeans are very popular with (17)________people all over the world. Some people say that jeans are the “uniform” of youth. But they haven’t always been popular. The story of jeans (18)________almost two hundred years ago. People in Genoa, Italy made pants. The cloth made in Genoa was (19)________“jeanos”. The pants were called “jeans”. In 1850, a salesman in California began selling pants made of canvas. His name was Levi Strauss. Because they were so strong, “Levi’s pants” became (20)________with gold miners, farmers and cowboys. Six years later Levis began making his pants with blue cotton cloth called denim. Soon after, factory (21)________in the US and Europe began wearing jeans. A: drivers B: farmers C: cowboys D: workers

Nguyên nhân chủ yếu nào thực dân phương Tây (đặc biệt là Anh, Pháp) lại tranh giành Ấn Độ? A: Chế độ phong kiến ở Ấn Độ đang phát triển. B: Ấn Độ là quê hương của những tôn giáo lớn. C: Ấn Độ có truyền thống văn hóa lâu đời. D: Ấn Độ đất rộng người đông, tài nguyên phong phú.