Bài 1: chọn 2 dung dịch mưới thích hợp để phân biệt 4 dung dich: BaCl2; HCl: K2SO4: Na3PO4 Baif2; làm thế nào nhận ra sự có mặt của mỗi khí trong hỗn hợp gồm: CO; CO2 và SO3

em hãy viết đoạn văn nghị luận (từ 20-30 dòng) giải thích câu nói:"tiên học lễ hậu học văn". ko hơn 35 dòng nhé!thanks trc ạ!

Rút gọn biểu thức : Giải từng bước giúp em vs ạ

Nhanh hộ mình nha, mình cho bạn đó hay nhất

Giải nhanh hộ em ik em vote 5* cho

Tìm x, biết: a) $x^{2}$ = 81 b) $x^{2}$ = -100 c) ($x-3)^{2}$ = 100 d) ($3x+5)^{2}$ = 49 e) ($3x+5)^{3}$ = 729 g) ($5x-2)^{2}$ = 100 h) ($5x+7)^{3}$ = 1000 k) ($4x-2)^{5}$ = 243 Help me

Combine These Pairs Of Sentences Using Relative Pronouns: WHO/THAT/WHICH/WHOSE... e.g. The students will be awarded the present. The students' reports are very valuable. ->The students whose reports are very valuable will be awarded the present. 1. The first boy has just moved. He knows the truth. 2. I don't remember the man. You said you met him at the canteen last week. 3. The only thing is how to go home. It make me worried. 4. The most beautiful girl lives city. I like her long hair very much. 5. He was Tom. I met him at the bar yesterday. 6. The children often go swimming on Sundays. They have much free time then. 7. They are looking for the man and his dog. They have lost the way in the forest. 8. The tree has lovely flowers. The tree stands near the gate of my house. 9. My wife wants you to come to dinner. You were speaking to my wife 10. The last man has just returned from the farm. I want to talk to him at once.

$\frac{x+1}{99}$+$\frac{x+2}{98}$+$\frac{x+3}{97}$+$\frac{x+4}{96}$=-4

giai cho minh bai 15 minh can gap lam trong 10p

Mìn cần lời giải của bài 12 ạ , mình cần gấp