1 haven't cleaned

2 will be

3 is sleeping - gets

4 is teaching

5 does - isn't going - is watching

6 have written

7 hadn't disturbed

8 have you worked

9 get  - get

6 studies - are trying

7 had stood

8 drove

9 have you studied

10 have waited - hasn't come

11 have lived

a. \(\sqrt{\left(2+\sqrt{7}\right)^2}=2+\sqrt{7}=2\dfrac{\sqrt{7}}{1}\)

c. \(5\sqrt{x^2-6x+9}=5\sqrt{\left(x-3\right)^2}=5\left(x-3\right)=5x-15\)

d. \(\sqrt{\left(2-\sqrt{5}\right)^2}+\sqrt{\left(\sqrt{5}-7\right)^2}=2-\sqrt{5}+\sqrt{5}-7=-5\)

a) \(\sqrt{\left(2+\sqrt{7}\right)^2}=\left|2+\sqrt{7}\right|=2+\sqrt{7}\)

b) \(\sqrt{4+2\sqrt{3}}=\sqrt{\left(\sqrt{3}+1\right)^2}=\sqrt{3}+1\)

c) \(5\sqrt{x^2-6x+9}=5\sqrt{\left(x-3\right)^2}=5\left|x-3\right|=5\left(3-x\right)=15-5x\)(do x<3)

d) \(\sqrt{\left(2-\sqrt{5}\right)^2}+\sqrt{\left(\sqrt{5}-7\right)^2}=2-\sqrt{5}+\sqrt{5}-7=-5\)

b: \(\sqrt{4+2\sqrt{3}}=\sqrt{3}+1\)

Bài 1: 

a: \(150_{10}=\text{10010110}_2\)

b: \(11001110_2=206_2\)

c: \(7E_{16}=126_{10}\)

1. seeing

2. working

3. to meet

4. talking/ to finish

5. asking

6. not to speak

7. carrying

8. overhearing

9. writing/ waiting

10. to avoid/ being

11. giving/ to speak

12. going/ saying

13. to persuade/ to agree

14. sneezing/ sitting

15. driving/ being

16. to start/ looking

17. to show/ to use

18. making/ to do

19. remaining/ to help/ to stay

20. listening/ hearing

21. camping

22. to be

23. to speak

24. to pay

25. to meet

26. not trying/ to solve

27. being

28. hunting

29. to be

30. working

31. going

32. to do

33. to bring

34. working

35. to buy

36. to inform

37. studying

38. to buy

39. to be fed

40. working

8 dm = 0,8 m
S xung quanh là:
(1,5 + 0,6) x 0,8 x 2 = 3,36 (m2)
S phần quét sơn là:
3,36 + (1,5 x 0,6) = 4,26 (M2)
D/s :