8x - 2x - 2sqrt(x + 2) - 4sqrt(1 - 3x) = 0

cho tam giác abc có ba goc nhỏ hơn 90 độ. các đường cao bd và ce cắt nhau tại h. a, chứng minh tam giác abc đồng dạng với tam giác ace. b, chứng minh hb.hd=hd.he. c, trên các đoạn thẳng bd và ce lấy lần lượt 2 điểm m và n sao cho góc amc= góc anb=90 độ. chứng minh rằng am=an

Write a paragraph (120 words) to answer the following question. 
“Should students only focus on academic subjects?”

This is part of a letter you receive from your new penfriend, Jenna. I've got one close friend who I spend a lot of time with. What about you? Tell me about your friends. How important are they to you? Now write a letter in about 80 words to your friend. Sign your name as Lan Huong.

Your english teacher has asked you to write a story for your school competion: you study must BEGIN with " I quickly started to popen the large box"

This is part of a letter you receive from an English friend, Jane.

    In your last letter, you said you had made some changes to your room. What does it look like now? What new furniture have you got? Tell me all about it!

-                  Now write a letter telling your friend about your room.

-                  Write your letter in about 80 - 100 words

write a letter telling your friend about your room

a) Giải phương trình: (x - 187)/13 + (x - 170)/15 + (x - 149)/17 + (x - 124)/19 = 10

tìm x thuộc z để biểu thức sau là số nguyên b=x^2+2x+1 / x^2-1