tặng bạn nhân dịp tết

Góc x'Oy' = góc xOy = 70^ovì 2 góc đối đỉnh thì bằng nhau.

vì \(\stackrel\frown{X'OY'}\)

đối đỉnh với \(\widehat{XOY}\)

nên \(\widehat{X'OY'=70^o}\)

Có ^^

KB khum

tham khảo

Việc phát hiện ra kim loại để làm công cụ lao động có ý nghĩa hết sức to lớn. Trước kia con người chỉ biết sử dụng đá để làm công cụ. Cho tới khoảng 4000 năm TCN, con người đã phát hiện ra đồng kim loại. Đồng kim loại rất mềm, nên chủ yếu dùng làm đồ trang sức. Sau đó họ biết pha đồng với thiếc và chì cho đồng cứng hơn, gọi là đồng thau. Từ đó, người ta đã đúc ra được các loại rìu, cuốc, thương giáo, lao, mũi tên, trống đồng,v.v...^[7]. Khoảng 3000 năm trước đây, cư dân ở Tây Á và Nam Âu là những người đầu tiên biết đúc và dùng đồ sắt để làm lưỡi cày, cuốc, liềm, kiếm, dao găm, v.v...

Nhờ có công cụ kim khí, con người có thể khai phá thêm đất hoang, tăng năng suất lao động, sản phẩm làm ra ngày càng nhiều, không chỉ đủ ăn mà còn dư thừa...

Mik xin cảm ơn bạn rất nhiều nhé.Vì bạn đã giúp mình trả lời câu hỏi này ạ🥰🥰

Viết lại bài với chính xác tương đối (không mắc lỗi nghiệm trọng)

My best friend is Thanh An. We came to the same Archimedes School, and we have been friends for 1 year. Thanh An is not short and not tall, he has a normal height. He had a short black hair and a big black eyes. He is very kind and smart, especially in Math. He is funny too, he makes me laugh even when I feel bad. I like to be friends with him. Because he is very smart at Math, we created a Zalo group to do our homework. I will tell you my secret: I sometimes copy his Math homework too (HAHAHA). I hope that I can be friends with him forever.

a) Ta có: \(\dfrac{3}{2}\sqrt{12}+\sqrt{75}-\sqrt{300}+\sqrt{27}\)

\(=3\sqrt{3}+5\sqrt{3}-10\sqrt{3}+3\sqrt{3}\)

\(=\sqrt{3}\)

b) Ta có: \(\sqrt{14-6\sqrt{5}}+\sqrt{9-4\sqrt{5}}\)

\(=3-\sqrt{5}+\sqrt{5}-2\)

=1

Lên mạng mak tra ấy đầy

- Dù trời mưa nhưng em vẫn đi học đúng giờ

1. I can't help you because I am very busy now.

2. He stayed at home last Friday as it rained heavily.

3. Since it is very hot, we turn on all the fans.

4. The students learn English very badly because it is very difficult.

5. As Miss Dung is very kind, many people like her.

6. We can do the excercises quickly since they are very easy.

7. Because they didn't review the lessons carefully, they didn't do the test wel..

8. As they are in a hurry, they can wait for you.

9. Nam didn't go to school on time since he got up late.

10. Because her clothes are old, she has to buy some new ones.

11. As your shoes are very dirty, you should put them in the corner of the room. 

12. We went to the seaside for the weekend since the air in the city was not fresh.

13. These pupils often get bad marks because they are very lazy.

14. As the play was very long, we went home before the end.

1. I can't help you because/since/as I am very busy now

2. He stayed at home last Friday because/since/as it rained heavily

3. We turn on all the fans because/since/as it is very hot

4. The students learn English badly because/since/as it is very difficult

5. Many people like Miss Duong because/since/as she is very kind

6. We can do the exercises quickly because/since/as they are very easy

7. They didn't do the test well because/since/as they didn't review the lessons carefully

8. They can't wait for you because/since/as they are in a hurry

9. Nam didn't go to school on time because/since/as he got up late

10. She has to buy some new clothes because/since/as her ones are old

11. You should put your shoes in the corner of the room because/since/as they are very dirty

12. We went to the seaside for the weekend because/since/as the air in the city was not fresh

13. These pupils often get bad marks because/since/as they are very lazy

14. We went home before the end because/since/as they play was very long