cho △ABC . Điểm O nằm trong tam giác , tia BO cắt cạnh AC tại I

a. so sánh OA và IA + IO , từ đó suy ra OA + OB < IA +IB

b. Chứng minh OA+OB<OA+CB

c. chứng minh OA + OB + OB <OC <AB + CA + CB

Exercise 8. Find and correct the mistakes

my best frend and l went to same school

this fridge isn't as· good as mine old one

1. Mr. Pike teaches history of arts. Mrs. May teaches history of music. (same subject) _______________________________________________________________________

 2. This bike is 800,000 VND. That bike is 600,000 VND. (price … different) _______________________________________________________________________.

3. My house is small and old. Your house is spacious and modern. (different from) _______________________________________________________________________.

4. Classical music is interesting. Folk music is interesting. (as … as) _______________________________________________________________________.

5. Mr. Owen speaks English. Mrs. Phan speaks English. (same language) _______________________________________________________________________.

6. Huyen My sings beautifully. Her sister sings more beautifully than her. (as … as)

Exercise 8. Find and correct the mistakes

Playing the piano is as difficult as play the guitar

2. Can a horse run same fast as a train?

3. You should try as hardly as you can

. 4. My writing style is totally same from Tom’s.

5.his car runs the same speed From mine

1. This cake is ____________________ that cake. (sweet) 2. My laptop is _________________________ yours. (expensive) 3. This actress acts _________________________ that one. (excellently) 4. Does a tiger run _________________________ a cheetah? (fast) 5. Simon is _________________________ his brother. (brave) 6. Is an elephant _________________________ a whale? (heavy) 7. Emma is _________________________ Judy. (studious) 8. Did he do the test _________________________ you? (badly) 9. I slept _________________________ my mother last night. (well) 10. Ben cooks _________________________ his friend. John. (badly) 

Chứng minh 3n +11 và 3n +2 là hai số nguyên tố cùng nhau với mọi số tự nhiên n

Học sinh khối 6 của một trường ủng hộ học sinh vùng lũ lụt một số sách giáo khoa trong khoảng từ 500 đến 600 cuốn . biết rằng nếu xếp 12 cuốn, 18 cuốn hay 30 cuốn thành một chồng thì vừa đủ ko thừa cuốn nào.Hỏi hs khối 6 đã ủng hộ bao nhiêu cuốn sách