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\(\left(m^2\right)\)

:))

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

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

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

1. was

2. are cleaning

3. smoke

4. to prepare

5. had gone

6. is going to rain

7. haven't finished

8. can go

9. 

10. studies

vài câu mình có thể sai nhé

1 phân tử C₂H₅OH có 5 liên kết C-H, 1 liên kết C-C, 1 liên kết C-O, 1 liên kết O-H

=> Năng lượng cần để phá vỡ 1 mol phân tử C₂H₅OH = 5.99 + 1.78 + 1.75 + 1.104,7 = 752,7 kcal/mol
=> B

1 F

2 T

3 T

4 T

mk cảm ơn

1 It was such old furniture that we can't keep it

2 Such is a popular play that the theater is likely to be full every night

3 Such was her hopelessness that Alice decided to stop her business

4 He bought so many books that he didn't know where to put them

5 It was such a boring film that we couldn't go on seeing it

6 So fast did he spoke that we couldn't understand him

7 The fair was too noisy for us to hear each other

8 You are such a fast speaker that i can't catch up with your words

9 It is such an untidy room that it took us one hour to clean it

10 They are such wonderful books that we have read them many times

12 It was such bad news that she burst into tears on hearing it