câu 2:
A=x^2.(x-2)-(x-1).(x^2+x+1)   giữ liệu x=-5
B=(5x+5)^2+10(x-3).(1+x)+x^2-6x+9  giữ liệu  x=1/2

EXERCISE I. Fill with suitable questions tag.  

1. She’s from a small town in China, .... ? 

2. He's still sleeping, .... ? 

3. We’re late again, .... ? 

4. I’m not the person with the tickets, .... ? 

5. You do go to school, .... ? 

6. The weather is really bad today, .... ? 

7. Let's go for a walk, .... ? 

8. They aren’t in Mumbai at the moment, .... ? 

9. We won't be late, .... ? 

10. John’s a very good student, .... ? 

11. Nobody called, .... ? 

12. She doesn’t work in a hotel, .... ? 

13. They will wash the car, .... ? 

14. We live in a tiny flat, .... ? 

15. We must lock the doors, .... ? 

16. David and Julie don’t take Chinese classes, .... ? 

17. I often come home late, .... ? 

18. I'm right, .... ? 

19. She doesn’t cook very often, .... ? 

EXERCISE II: Add tag questions to the following. 

1. Lan enjoys watching TV after dinner, ............? 

2. Tam didn't go to school yesterday, ........? 

3. They'll buy a new computer, .........? 

4. She can drink lots of tomato juice every day, .............? 

5. She may not come to class today, .............? 

6. We should follow the traffic rules strictly, .............? 

7. Your mother has read these fairy tales for you many times, .............? 

8. He seldom visits you, .............? 

9. You've never been in Italy, .............? 

10. That's Bob, .............? 

11. No-one died in the accident, .............? 

12. I'm supposed to be here, .............? 

13. Nothing is wrong.............? 

14. Nobody called the phone, .............? 

15. Everything is okay, .............? 

16. Everyone took a rest, .............? 

17. Going swimming in the summer is never boring, .............? 

18. Let's dance together, .............? 

19. Don't talk in class, .............? 

20. Sit down, .............? 

21. This picture is yours, .............? 

22. Hoa never comes to school late, .............? 

23. You took some photos on the beach, .............? 

24. He hardly ever makes a mistake, .............? 

Cho tam giác ABC cân tại A , trung tuyến AM. Qua điểm B vẽ đường thẳng song song với đường thẳng AC cắt đường thẳng AM tại điểm D

a)Chứng minh : tam giác ABC = tam giác DMB

b)Chứng minh : AB=BD

c)Gọi P là trung điểm của đoạn thẳng AB , đoạn thẳng PD cắt đoạn thẳng BC tại O. Trên tia đối của tia PO lấy điểm N sao cho PN=PO. Chứng minh điểm O là trọng tâm của tam giác ABD và NA=2OM