1: \(2155-\left(174+2155\right)+\left(-68+174\right)\)

=2155-174-2155-68+174

=(2155-2155)+(174-174)-68

=-68

2: \(-25\cdot72+25\cdot21-49\cdot25\)

\(=25\left(-72+21-49\right)\)

\(=25\cdot\left(-100\right)=-2500\)

3: \(35\left(14-23\right)-23\left(14-35\right)\)

\(=35\cdot14-35\cdot23-23\cdot14+23\cdot35\)

\(=35\cdot14-23\cdot14=12\cdot14=168\)

4: \(8154-\left(674+8154\right)+\left(-98+674\right)\)

=8154-674-8154-98+674

=(8154-8154)+(674-674)-98

=0+0-98

=-98

5: \(-25\cdot21+25\cdot72+49\cdot25\)

\(=25\left(-21+72+49\right)\)

\(=25\cdot100=2500\)

6: \(27\left(13-16\right)-16\left(13-27\right)\)

\(=27\cdot13-27\cdot16-16\cdot13+16\cdot27\)

\(=27\cdot13-16\cdot13=11\cdot13=143\)

7: -1911-(1234-1911)

=-1911-1234+1911

=-1234

8: \(156\cdot72+28\cdot156\)

\(=156\cdot\left(72+28\right)\)

\(=156\cdot100=15600\)

9: \(32\cdot\left(-39\right)+16\cdot\left(-22\right)\)

\(=16\cdot\left(-78\right)+16\cdot\left(-22\right)\)

\(=16\cdot\left(-78-22\right)=16\cdot\left(-100\right)=-1600\)

10: -1945-(567-1945)

=-1945-567+1945

=-567

11: \(184\cdot33+67\cdot184\)

\(=184\cdot\left(33+67\right)\)

\(=184\cdot100=18400\)

12: \(44\cdot\left(-36\right)+22\cdot\left(-28\right)\)

\(=22\cdot\left(-72\right)+22\cdot\left(-28\right)\)

\(=22\cdot\left(-72-28\right)=22\cdot\left(-100\right)=-2200\)

a: AG=CD-FE+BC=5-3+2=2+2=4(m)

AB=GF+ED-BC=6+7-2=11(m)

Chu vi mảnh vườn là 11+2+2+5+7+3+6+4=40(m)

b:

AM=NE+ED=6+7=13(m)

AN=MD=MK+KD=2+5=7(m)

Diện tích hình chữ nhật AMDN là:

\(S_{AMDN}=AM\cdot AN=13\cdot7=91\left(m^2\right)\)

Diện tích hình chữ nhật GFEN là:

\(S_{GFEN}=GF\cdot FE=6\cdot3=18\left(m^2\right)\)

Diện tích hình vuông BMKC là:

\(S_{BMKC}=2\cdot2=4\left(m^2\right)\)

Diện tích của cả hình là:

91-18-4=91-22=69\(\left(m^2\right)\)

C 

c

9.      She dislikes talking to strangers.

10.  This camera was bought 2 days ago.

11.  Lan is both clever and beautiful.

12.  Unless you phone her, she will be very sad.

13.  They are independent. (self-reliant/self-sufficient)

14.  Do you mind arranging flowers?

28. richness

29. unpopular

30. popularity

31. unpopularity

32. limitations

33. excited

34. further

35. familiarize

36. Originally

37. confusing

38. confusion

39. reducing

40. extremely

41. environmentalists