7. to be 

8. to do, to ask 

9. staying 

10. to see 

11. staying 

12. to doing 

13. signing 

14. doing 

15. eating 

16. to work, to do, to do

17. to enable, to do 

18. to be 

19. quarreling 

20. doing 

21. to dare to tell 

22. not to do 

23. taking part 

24. to see 

25. try to convince, to join 

26. to write, to do 

27. to do, to enable, doing, having

28. living

29. to travel, doing

30. not to go

31. to persuade, helping

32. to dare to object, to tell

33. to have, to finish

34. to be, helping

35. to pass

36. to tell

37. arranging to do

38. to see, to postpone doing

39. to argue

40. to urge to finish

41. to sign

42. to be

43. to delay

44. going 

=>x(x^2-9/16)=0

=>x(x-3/4)(x+3/4)=0

=>x=0; x=3/4; x=-3/4

hình bé quá

sin 65⁰=cos 35⁰
\(cos70^0=sin30^0\)
\(tan80^0=cot20^0\)
\(cot68^0=tan32^0\)

Ko nhìn chữ bn ơi, bn cho to hình một tý

Part 6 : 

1. especially

2. with

3. goods 

4. perform

Part 7: 

1. T

2. F

3. F

4.T

Câu 14 : 

\(n_{H_2SO_4}=0.15\cdot2=0.3\left(mol\right)\)

\(2KOH+H_2SO_4\rightarrow K_2SO_4+2H_2O\)

\(0.6..........0.3\)

\(m_{KOH}=0.3\cdot56=33.6\left(g\right)\)

\(m_{dd_{KOH}}=\dfrac{33.6}{40\%}=84\left(g\right)\)

Câu 13 : 

\(n_{HCl}=2\cdot0.6=1.2\left(mol\right)\)

\(\Rightarrow n_{H_2O}=\dfrac{1}{2}\cdot1.2=0.6\left(mol\right)\)

Bảo toàn nguyên tố O : 

\(n_{O\left(oxit\right)}=n_{H_2O}=0.6\left(mol\right)\)

\(\Rightarrow m_O=0.6\cdot16=9.6\left(g\right)\)

\(m_{Fe}=34.8-9.6=25.2\left(g\right)\)

\(n_{Fe}=\dfrac{25.2}{56}=0.45\left(mol\right)\)

\(n_{Fe}:n_O=0.45:0.6=3:4\)

\(CT:Fe_3O_4\)

\(m_{Muối}=m_{oxit}+m_{HCl}-m_{H_2O}=34.8+1.2\cdot36.5-0.6\cdot18=67.8\left(g\right)\)

Câu 4 : C

Câu 5 : 28,26 cm²

/HT\

Câu 4. A

Câu 5. 3 nhân 3 nhân 3,14  = 28,26 ( cm2 )

2,Có \(\widehat{A}+\widehat{D}=180^0\) (Hai góc trong cùng phía do AB//CD)

\(\Rightarrow\widehat{D}=180^0-115^0=65^0\)

Ta có: AB//CD

nên \(\widehat{A}+\widehat{D}=180^0\)

hay \(\widehat{D}=65^0\)

26 A

27 C

28 B

29 A

30 B

31 A

32 B

33 A

34 C

35 A