đề đâu bn 

16 C

17 E

18 G

19 B

20 A

Test 3

1 E

2 C

3 A

4 G

5 B

Part 6

36 book

37 reception

38 tent

39 double

Part 2

6 B

7 C

8 A

9 C

10 A

Part 3

11 A

12 B

13 A

14 B

15 C

16 C

17 D

18 H

19 A

20 E

lần lượt nhé

đăng lại làm gì bn ?

n+3\(⋮\)n+1

=> n+1+2\(⋮\)n+1

=> 2\(⋮\)n+1

=> n+1 \(\in\)1,2,-1,-2

=> n \(\in\)-2,1-3,-4

cám ơn , kb nha 

\(n+3⋮n+1\)

\(n+3=n+1+2⋮n+1\)

               mà \(n+1⋮n+1\)

\(\Rightarrow2⋮n+1\)

\(\Rightarrow n+1\inƯ\left(2\right)\)

Vậy \(n\in\left\{0;1\right\}\)

nếu sai thì cho mk xin lỗi nhé

:D?

Bài 3

1 recycle

2 clear

3 many

4 bottles

5 dishes

Bài 4

1 plastic

2 colours

3 glass

4 good

5 car

Bài 5

1 will drive

2 writes

3 will get angry

4 will go

5 doesn't pass

6 will learn

7 will go

8 doesn't cost

9 will catch

10 don't feel

Bài 6

1 If I can't sleep, I will get up and read book

2 If it is nice, I will go for a picnic on the river bank

3 If she works hard all the time, she will pass the exam

4 If she travels a lot, she will be very tired

5 If people pollute the air, our environment will have many problems

6 If we make an excess of noise in the outdoors, we will have noise pollution

7 If we use too many artificial chemicals, we will have soil pollution

8 If people use too much bright lighting in big cities, they will have light pollution

9 If Peter doesn't arrive on time, he will miss the train

10 If you don't finish your homework, you will get the bad marks

Bài 8

1 make

2 save

3 collect

4 put

5 turn off

6 give

7 write

8 put

9 save

10 keep

46 Are there 4 people in your family

47 How crowded the city is!

48 What's the price of this pair of shoes

49 Minh often goes to work by car

50 taking part in the singing contest

a: Xét ΔEAD và ΔECG có

góc EAD=góc ECG

góc AED=góc CEG

=>ΔEAD đồng dạng với ΔECG

=>AD/CG=ED/EG

=>AD*EG=ED*CG

b: Xét ΔHEG và ΔHCB có

góc HEG=góc HCB

góc EHG=góc CHB

=>ΔHEG đồng dạng với ΔHCB

=>HE/HC=HG/HB

Xét ΔHAB và ΔHCG có

góc HAB=góc HCG

góc AHB=góc CHG

=>ΔHAB đồng dạng với ΔHCG

=>HA/HC=HB/HG

=>HC/HA=HG/HB

=>HC/HA=HE/HC

=>HC^2=HA*HE

c: HI//BA

=>HI/BA=CH/CA=CI/CB

HI//EG

=>HI/EG=BI/BC

HI/BA=CI/CB

HI/BA+HI/EG=BI/BC+CI/BC=1

=>HI(1/BA+1/EG)=1

=>1/BA+1/EG=1/HI

a: Xét ΔAHB vuông tại H và ΔCHA vuông tại H có

góc HAB=góc HCA

=>ΔAHB đồng dạng với ΔCHA

b,c: góc FAE+góc FHE=180 độ

=>FAEH nội tiếp

=>góc HFE=góc HAE=góc C

Xét ΔHFE vuông tại H và ΔHCA vuông tại H có

góc HFE=góc HCA

=>ΔHFE đồng dạng với ΔHCA

=>HF/HC=HE/HA

=>HF*HA=HC*HE