bài 1:tính 734-46= 356+90= 757+690-90+78= 567+54-58= giúp với nha

Cho tứ giác lồi ABCD có 4 đỉnh thuộc đường tròn (O). Gọi Ha ,Hb ,Hc ,Hd lần lượt là trực tâm các tam giác BCD, CDA, DAB, ABC. Chứng minh rằng AHa ,BHb ,CHc ,DHd đồng quy.

giúp mk nhá, ít điểm quá mn thông cảm

Sông và hồ khác nhau như thế nào ? Nếu giá trị kinh tế của sông ngòi nước ta

Cho a+b=2 .cmr :B=a^5 +b^5 ≥ 2

Correct the mistakes: a. When I will go to school tomorrow, I’ll tell you about our plan. b. He ate a lot of green apples , and he has a stomachache now. c. I find sewing is very useful. d. Mr. Tuan is a farmer. He loves work on the farm. e. I think eat too much meat is not good for our health. f. You are putting on weight. Do more exercises and to eat less fatty food. - Has peer- correction first, then gives the key II: Complete each sentence so it means the same as the sentence above. 1. I didn’t go to school because I was sick. à I was sick, so ………………. 2.It will be good if you eat less meat and more vegetables. à You should ……………… 3. He likes playing computer games in his free time. à His hobby is …………….. 4. I am interested in watching TV in the evening. à I enjoy ………………… 5.I think that learning English is important. à I find ………………….. III. Choose a-f to complete the conversation Mi:   Nga, what is your favorite hobby? Nga : (1)……………………………….. Mi:   Why? Nga  (2)……………………………….. Mi:   When did you start your hobby? Nga  (3)……………………………….. Mi:   Do you share this hobby with anyone? Nga  (4)……………………………….. Mi:   Is it difficult to cook? Nga  (5)……………………………….. Mi:   Where do you get the recipes? Nga (6)……………………………….. a. I don’t think it’s difficult because I like it very much. b. I love cooking c. Most of the time learn from my mom. Sometimes I get them from the internet. d. It’s great when I see  other people enjoy my food. e. yes. My mom love it too. f. When I was six years old, my mom taught me how to cook my first dish.

Giải phương trình $\sqrt{2x^{2}-3}+\sqrt{2x^{2}-5x+3}=\sqrt{2x^{2}-7x+6}$

cho hình thang vuông ABCD (AB // CD, A = D = 90 độ). Biết đáy lớn CD = BC = 2 AB. Kẻ BH vuông góc CD tại H. Chứng minh: a) AB = DH => DH= HC. b) tam giác BDC đều c) tính góc A, góc B, góc C

tìm tập xác định của hàm số lượng giác

Happy birthday hoi dap Fanart lại tranh dứoi