Bài 1 : Cho tam giác ABC ( góc A = 90 độ ) . Biết AB= 21 cm , AC = 28 cm , đường cao AH a, Tính BC ? góc B ? góc C ? b, Gọi M và N lần lượt là hình chiếu của H trên AB và AC . Tính độ dài MN c, Tam giác ABC có thêm điều kiện gì để tứ giác AMHN là hình vuông ?

Giúp tớ với Nhanh lên!!! Cần gấp!!! Please, help me!!!!!! Chỉ có 1 bài này thôi!!! Nha, giúp đi mà!!!

Tìm x,y ∈ Z x^2 +xy +y^2 = x^2y^2

1×2+2×3+...+299×300/1×299+2×298+...+299×1

1. My sister is not as hard - working as me ( I) 2.The movie theater is behind the bakery. ( The bakery) 3. Linh is Ms.Anh 's student( Ms. Anh 4. How will the weather be tomorrow?( What) 5. Minh would like some bread because he is hungry. ( Minh is) 6.No girl at school is as pretty as An. ( An) 7.My mother drove her car to the country yesterday. ( My mother went ) 8. The classroom has thirty desks. ( There) 9.Long is weaker than Hung ( Hung) 10. i like Maths best ( Maths) Mn người giúp mik vơi ah Đây là bài chia động từ ah

(X + 5)(x - 5) -(x-3)(x^2-3x+9)=5-x(x^2-x-2)

Có 4 ống nghiệm, mỗi ống chứa 1 dung dịch muối (không trùng kim loại cũng như gốc axit) là: clorua, sunfat, nitrat, cacbonat của các kim loại Ba, Mg, K, Pb. a, Hỏi mỗi ống nghiệm chứa dung dịch của muối nào? b, Nêu phương pháp phân biệt 4 ống nghiệm đó?.

Phân tích thành nhân tư (phối hợp) 1) 3x^5y^3+3x^2y^6 2) 2(a+b)³+16 3) ab(x-y)³+8ab 4) 27xy +xy(a+b)³ 5) 8xy³+x(x-y)³ 6) (a+b)³+c³

Fill in the blank with a suitable word Ethan and Noah are brothers. They look (1) ………………. each other but they are quite different in some ways. Noah likes to stay inside. He likes to watch television, and he watches several shows every day. He spends about two hours (2) ………………. television each day. He also likes (3) ………………. video games. He also loves (4) ………………. the Internet. He likes chatting with his friends and playing games online. In contrast, Ethan likes to spend time outside. He likes to swim in a pool which is not far (5) ……………. his house. He goes to the pool several times each week, sometimes everyday. He swims (6) ……………. about an hour. He walks there and back. Sometimes he runs all the (7) …………. there! On some days, Ethan plays basketball with his friends. Ethan (8) ………………. watch much television. He spends most of his day on his feet. Decide if the statements are true (T) or false 1. The brothers are similar in terms of their appearance. 2. Noah likes doing outdoor activities. 3. Noah often spends time with electric or technological devices. 4. Ethan goes swimming very often. 5. Ethan always walks to the swimming pool. X Read the passage. Fill in the statements with a suitable word/phrase from the passage. A favourite winter activity is skating. But before you go skating on a pond or lake, there are a few safety tips you should know. The ice should be at least 6 inches thick. Never skate alone. Never assume the ice is safe, and do not go out onto the ice after an animal or toy. Always be familiar with the area where you want to skate, and be sure it is well-lit if you go skating at night. The safest place to go skating is on a skating rink. Some cities have outdoor skating rinks. And most cities have an indoor skating rink you can use for a small fee. When you go skating for the first time, make sure you wear warm socks, a warm hat, and lots of layers of clothing. Most rinks have hot drinks and snacks, but you can also bring your own snacks. Weekends are usually the busiest time of the week to go skating. Weekday nights are usually less crowded. Evening skating can be a lot of fun for the whole family. Most rinks have floodlights. At night, the rink is lit up and bright. 1. The thickness of the ice should be …………… as minimum. 2. When you go for night skating, it is essential that the skating area is …………… 3. To be safest, you shouldn’t go out of the …………… 4. You need to pay a …………… to use indoor skating rink. 5. You should wear …………… clothes when going skating. 6. If you forget to bring foods and drinks, you may get …………… at the rinks. 7. If you don’t like having many people at the rink, you can go at …………… 8. Evening skating can be a good activity for the whole ……………

Sửa giúp em với nhé 😊 em cảm ơn ạ 😺