hãy cho biết dãy chất nào sau đây đổi màu quỳ tím sang đỏ: A. CH3-CH(NH2)-COOH; CH3COOH; HOOC-CH2-CH(NH2)-COOH B. H2N-CH2-COOH; HOOC-CH2-CH2-CH(NH2)-COOH; CIH3N-CH2-COOH C. CH3-CH(NH2)-COONa; H2N-CH2-COOCH3; H2N-CH2-CH2-CH(NH2)-COOH D. CIH3N-CH2COOCH3; HOOC-CH2-CH(NH2)-COOH; CIH3N-CH2COOH

Cho tam giác ABC vuông tại A , đường cao AH . Biết AB = 12cm , AH = 7,2cm . a,Tính AC , BC . b, Kẻ HE vuông AB tại E , HF vuông AC tại F . Chứng minh AE.AB = AF.AC. c, Chứng minh EA.EB + FA.FC = AH2

Giúp mình với ạ Làm câu nào cũng được

Một ô tô đi quãng đường 27 km trong 27 phút. Vận tốc ô tô đó là A100m/phút B.60km/giờ C.100km/giờ D.12,15km /giờ

lm gấp cho mk vs , mk cảm ơn ak

II- Complete each sentence with a, an, the or X . 6. She will come back in ………………………hour. 7. Kate has bought .......................... new car. 8. Some people think that .......................... moon is made of cheese! 9. I’m collecting money for .......................... poor. 10. Brian hasn’t found .......................... job yet. 11. Can you play ...........the............... guitar? 12. Don’t forget to turn off .......................... television. 13. ……………pets are not allowed in this hotel. 14. They have ……………loveliest garden I have ever seen. 15. On our trip we visited ……………..Lake Victoria. III- Circle the correct answer. 16. Is this a person / the person you told me about? 17.This is the only cinema/an only cinema in the area. 18. The computer / Computer has already changed our lives dramatically. 19. Philip has just bought the Thames barge / a Thames barge. 20. Are you going to church / the church on Sunday?

Cho mình hỏi là nếu dùng máy tính thì cần làm gì để khi mình tắt máy tính và khi bật lại thì những trang wed lúc chưa tắt vẫn giữ nguyên ban đầu ạ ?

Exercise 5. Write questions using do you think…..will ……..? + one of these verbs: be back cost finish get married happen like rain 1. I’ve bought Mary a present. - Do you think she’ll like it?. 2. The weather doesn't look very good. Do you ……………………………………………….? 3. The meeting is still going on. When do you……………………………………………….? 4. My car need to be repaired. How much……………………………………………….? 5. Sally and David are in love. Do……………………………………………….? 6. "I'm going out now". "OK. What time ……………………………………………….? 7. The future situation is uncertain. What……………………………………………….?

giúp mình câu b plssssssssssssssssssssssssssssssssssssssssss

Giúp mk vs!!! Mk cần gấp ạ.Giúp mk thì mk sẽ đánh giá 5 sao