Bài 2: Chọn C

Bài 4: 

a: \(\widehat{C}=180^0-80^0-50^0=50^0\)

Xét ΔABC có \(\widehat{A}=\widehat{C}< \widehat{B}\)

nên BC=AB<AC

b: Xét ΔABC có AB<BC<AC

nên \(\widehat{C}< \widehat{A}< \widehat{B}\)

10. ……………. festival do you choose? - I choose Elephant Race Festival.

A. What B. How C. Which D. When

11. ……………. often is Burning Festival held? - It's held every year.

A. Which B. When C. What D. How

12. ……………. does the teacher say La Tomatina sounds unusual? - Because people throw tomatoes at each other for one hour at the festival.

A. What B. When C. Why D. How

13. He ___________ books for poor children for years.

A. has collected B. collects C. is collecting D. collected

14. Next Saturday at this time, we _____ on the beach in Mexico.

A. will relax B. will be relaxing C. has relaxed D. relax

15. Anne and Joe _____ by sea tomorrow

A. travel B. will travel C. travels D. travelled

16. I_____ in Jakarta, but now I live in New York. [use to + V-inf]

A. used to living B. used to living C. used to live D. am used to live

17. Jane_____ for the telephone company, but now she has a job at the post office.

A. used to working B. used to worked C. is used to work D. used to work

18. …………. he spent much money on the film, it wasn't a big success.

A. Even B. But C. Although D. Despite

19. We didn't find it funny………..it was a comedy.

A. in spite of B. despite C. although D. but

20. I went to the cinema with my friends yesterday ………… feeling very tired.

A. although B. in spite C. despite D. but

21. Let's go to the Victor Cinema. I'm sure you'll find the film…………

A. excites B. excite C. excited D. exciting

22. I was ……… to learn that the director of that gripping film has won the first prize.

A. interest B. interests C. interested D. interesting

23. The film was boring, ____ we went home.

A. so B. when C. but D. if

24. Nam was absent from class yesterday ____ he felt sick.

A. so B. because C. although D. but

25. These books aren’t yours, ____________?

A.are these B. aren’t these C. are they D. aren’t they

26. No one died in the accident, ______________?

A.did they B. didn’t they C. did he D. didn’t he

27. Tom knows Alice, _____________?

A.doesn’t he B. is he C. does he D. isn’t he

28. Peter never comes to class late, ________________?

A. doesn’t he B. doesn’t Peter C. does he D. does Peter

29. ……… computer is a laptop, but ……… is a desktop.

A. Hers - you B. Her - your C. My - yours D. Mine - yours

30. We gave them ……… ID number, and they gave us ……….

A. ours - theirs B. our - theirs C. our -their D. ours - their

Mn giúp mik ak câu nào mn bt thì lm còn lm hết đc thì càng tốt nhé TKS

10. ……………. festival do you choose? - I choose Elephant Race Festival.

A. What B. How C. Which D. When

11. ……………. often is Burning Festival held? - It's held every year.

A. Which B. When C. What D. How

12. ……………. does the teacher say La Tomatina sounds unusual? - Because people throw tomatoes at each other for one hour at the festival.

A. What B. When C. Why D. How

13. He ___________ books for poor children for years.

A. has collected B. collects C. is collecting D. collected

14. Next Saturday at this time, we _____ on the beach in Mexico.

A. will relax B. will be relaxing C. has relaxed D. relax

15. Anne and Joe _____ by sea tomorrow

A. travel B. will travel C. travels D. travelled

16. I_____ in Jakarta, but now I live in New York. [use to + V-inf]

A. used to living B. used to living C. used to live D. am used to live

17. Jane_____ for the telephone company, but now she has a job at the post office.

A. used to working B. used to worked C. is used to work D. used to work

18. …………. he spent much money on the film, it wasn't a big success.

A. Even B. But C. Although D. Despite

19. We didn't find it funny………..it was a comedy.

A. in spite of B. despite C. although D. but

20. I went to the cinema with my friends yesterday ………… feeling very tired.

A. although B. in spite C. despite D. but

21. Let's go to the Victor Cinema. I'm sure you'll find the film…………

A. excites B. excite C. excited D. exciting

22. I was ……… to learn that the director of that gripping film has won the first prize.

A. interest B. interests C. interested D. interesting

23. The film was boring, ____ we went home.

A. so B. when C. but D. if

24. Nam was absent from class yesterday ____ he felt sick.

A. so B. because C. although D. but

25. These books aren’t yours, ____________?

A.are these B. aren’t these C. are they D. aren’t they

26. No one died in the accident, ______________?

A.did they B. didn’t they C. did he D. didn’t he

27. Tom knows Alice, _____________?

A.doesn’t he B. is he C. does he D. isn’t he

28. Peter never comes to class late, ________________?

A. doesn’t he B. doesn’t Peter C. does he D. does Peter

29. ……… computer is a laptop, but ……… is a desktop.

A. Hers - you B. Her - your C. My - yours D. Mine - yours

30. We gave them ……… ID number, and they gave us ……….

A. ours - theirs B. our - theirs C. our -their D. ours - their

ta có Cu ko tác dụng được vs H2SO4 

-> 2,24 lít khí H2 đc tạo ra là do phản ứng HH của Fe va H2SO4 

\(PTHH:\) \(Fe+H_2SO_4->FeSO_4+H2\)

n H2 = 2,24 :22,4=0,1 mol 

n H2 = n Fe =0,1 mol 

m Fe = 0,1.56=5,6 g 

m Cu = 10-5,6=4,4 g 

vậy giá trị của x là 4,4 g

26 

PTHH : \(Zn+2HCl->ZnCl_2+H_2\)

n Zn = 6,5:65=0,1 mol

n ZnCl2 = n Zn =0,1 mol

m ZnCl2 = 0,1.(65+35,5.2)=13,6 g

Bài 3:

Kẻ BH⊥DC tại H

Xét tứ giác ABHD có \(\hat{BAD}=\hat{ADH}=\hat{BHD}=90^0\)

nên ABHD là hình chữ nhật

=>AD=BH; AB=DH

=>DH=7cm; BH=8cm

ΔBHC vuông tại H

=>\(BH^2+HC^2=BC^2\)

=>\(HC^2=BC^2-BH^2=10^2-8^2=36=6^2\)

=>HC=6(cm)

DC=DH+HC=7+6=13(cm)

Bài 2:

Xét ΔPBM và ΔPAQ có

\(\hat{PBM}=\hat{PAQ}\) (hai góc so le trong, BM//AQ)

PB=PA

\(\hat{BPM}=\hat{APQ}\) (hai góc đối đỉnh)

Do đó: ΔPBM=ΔPAQ
=>PM=PQ

=>P là trung điểm của MQ

Xét tứ giác AMBQ có

P là trung điểm chung của AB và MQ

=>AMBQ là hình bình hành

Hình bình hành AMBQ có \(\hat{MAQ}=90^0\)

nên AMBQ là hình chữ nhật

=>\(\hat{BQA}=90^0\)

=>BQ⊥AC tại Q

Xét ΔABC có

AI,BQ là các đường cao

AI cắt BQ tại H

Do đó: H là trực tâm của ΔABC

ΔAIB vuông tại I

mà IP là đường trung tuyến

nên \(IP=\frac{AB}{2}\)

mà \(\frac{AB}{2}=\frac{MQ}{2}=PQ\) (AB=MQ)

nên PI=PQ

=>ΔPIQ cân tại P

Bài 7:

\(a,A=\dfrac{2a+a-3}{a-3}\cdot\dfrac{\left(a-3\right)\left(a+3\right)}{3}=\dfrac{3\left(a-1\right)\left(a+3\right)}{3}=\left(a-1\right)\left(a+3\right)\\ b,B=\dfrac{b+3-6}{b+3}:\dfrac{b^2-9-b^2+10}{\left(b-3\right)\left(b+3\right)}\\ B=\dfrac{b-3}{b+3}\cdot\left(b-3\right)\left(b+3\right)=\left(b-3\right)^2\)

Bài 8:

\(a,M=\dfrac{4m^2-4mn+n^2}{m^2}:\dfrac{n-2m}{mn}=\dfrac{\left(n-2m\right)^2}{m^2}\cdot\dfrac{mn}{n-2m}=\dfrac{n\left(n-2m\right)}{m}\\ b,N=\dfrac{1}{3}+x:\dfrac{x+3-x}{x+3}=\dfrac{1}{3}+x\cdot\dfrac{x+3}{3}=\dfrac{1+x^2+3x}{3}\)

Bài 8: 

b: \(N=\dfrac{1}{3}+\dfrac{x}{\dfrac{x+3-x}{x+3}}=\dfrac{1}{3}+\dfrac{x}{\dfrac{3}{x+3}}=\dfrac{1}{3}+\dfrac{x+3}{3x}=\dfrac{x+x+3}{3x}=\dfrac{2x+3}{3x}\)

Câu 106: 

a: Xét ΔABC có 

P là trung điểm của AB

N là trung điểm của AC

Do đó: PN là đường trung bình của ΔABC

Suy ra: PN//BC

hay PN//HM; QN//HM

Xét tứ giác QNMH có QN//HM

nên QNMH là hình thang

mà \(\widehat{QHM}=90^0\)

nên QNMH là hình thang vuông

b: Ta có: ΔAHC vuông tại H

mà HN là đường trung tuyến ứng với cạnh huyền AC

nên \(HN=\dfrac{AC}{2}\left(1\right)\)

Xét ΔABC có

M là trung điểm của BC

P là trung điểm của AB

Do đó: MP là đường trung bình của ΔABC

Suy ra: MP//AC và \(MP=\dfrac{AC}{2}\left(2\right)\)

Từ (1) và (2) suy ra MP=HN

Xét tứ giác MNPH có PN//HM

nên MNPH là hình thang

mà MP=HN

nên MNPH là hình thang cân

bạn đinhr thực sự hâm mộ bạn luôn á cam rơn nhìu nha mong bn sẽ luôn giúp đỡ mik :)