a) Điểm - 2 cách điểm 2 là .......4......đơn vị theo chiều .......âm........

b) Điểm 1 cách điểm -3 là ....4...đơn vị theo chiều .....dương......

Tên: Nguyễn Hữu Thi

Lớp: 7

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mị bk là k có giải r` nhg mà đăng kí cho vui :3

Oxi hóa 1,200 gam CH 3 OH   bằng CuO nung nóng, sau một thời gian thu được hỗn hợp sản phẩm X (gồm HCHO, H 2 O và  CH 3 OH    dư). Nếu cho toàn bộ hỗn hợp X tác dụng với Na dư, thu được lượng khí hiđro có thể tích (đktc) bằng

A. 0,054 lít.

B. 0,840 lít.

C. 0,420 lít.

D. 0,336 lít.

a) Ta có: BD = BA (gt) \(\Rightarrow\Delta BAD\) cân tại B

\(\Rightarrow\) \(\widehat{BAD}=\widehat{BDA}\)

b) Trong \(\Delta ADH\) vuông tại H có: \(\widehat{DAH}+\widehat{ADH}=90^o\)

mà \(\widehat{BAD}+\widehat{DAK}=90^o\)

\(\Rightarrow\) \(\widehat{DAH}+\widehat{ADH}=\widehat{BAD}+\widehat{DAK}\)

mà \(\widehat{ADH}=\widehat{BAD}\) (cmt)

\(\Rightarrow\)\(\widehat{DAH}=\widehat{DAK}\)

\(\Rightarrow\) AD là tia phân giác của góc HAC

c) Xét \(\Delta ADH,\Delta ADK\) có:

\(\widehat{H}=\widehat{K}=90^o\)

AD là cạnh chung

\(\widehat{DAH}=\widehat{DAK}\) (cmt)

\(\Rightarrow\Delta ADH=\Delta ADK\) (cạnh huyền - góc nhọn)

d) Ta có: KC < DC (\(\Delta KDC\) vuông tại K)

mà KC = AC - AK

DC = BC - BD

\(\Rightarrow\) AC - AK < BC - BD

\(\Rightarrow\) AC + BD < BC + AK

mà BD = BA (gt)

AK = AH (cmt)

\(\Rightarrow\) AC + AB < BC + AH

Ex 3. Hãy điền từ thích hợp vào các câu sau.

1. I listen ........to....... music every night.

2. Stand ........up......., please.

3. Sit ........down......., please.

4. Lan is ........in....... grade 6.

5. They go .......to........ school every morning.

6. I get up ........at....... 6.00 every morning.

7. We live ........in....... a big city.

8. I’m ........in....... class 7ª.

9. They have English ........on....... Monday.

10. My house is ........on....... Le Loi street.

Ex 4. Hãy trả lời các câu hỏi sau, dùng từ gợi ý:

1. Who is this? -> ........This....... ........is....... Miss Lan.

2. Is she a nurse? -> Yes, ........she....... ........is.......

3. Who are they? -> ........They....... ........are....... Lan and Hoa.

4. What do they do? à ........They....... ........are....... students.

5. What’s that? à ........That's....... ........an....... eraser.

6. Is he a doctor? à No, ........he....... ........isn't.......

7. What’s this? à ........It's....... ........a....... desk.

8. Are they engineers? Yes, ........they....... ........are.......

9. How many brothers and sister do you have?

à .......I........ ........have....... two brothers and two sisters.

10. What time does Hoa get up every morning?

à .......She........ ........gets....... ........up....... ........at....... 6.00.

1) I have 5 books. He has 10 books.

-> I have fewer books than him.

-> He has more books than me.

2) There is more milk in the bottle than in the glass.

-> There is less milk in the glass than in the bottle.

3) I can drink 2 cans of beer. You can drink 3 cans.

-> You can drink more beer than me.

-> I can drink less beer than you.

4) I have less free time than you.

-> You have more free time than me.

5) He has fewer friends than Hoa.

-> Hoa has more friends than him.

6) You have mỏe homework than us

-> We have less homework than you.

overpopulation proplems ... both the rich ang the poor

A. cause

B.reduce

C.happen

D.affect

3ⁿ=3²

=>n=2

Read this passage then write True/ False

Nowsday, football becomes one of the world's most popular games. Millions of people play and watch it all around the world

A football match often has two parts. Each part is forty-five minutes. The first part is the first half and the second part is the second half. There is fifteen-minute break between two halve

There are two teams in a football match. Each football team has eleven players, including a goal- keeper. The players on the ground try to kick the ball into the other's goal. The team which scores more goals wins the match

1. ___T___ Today, football becomes very popular all around the world

2. ___T___ Millions of people play football

3. ___T___ A football match has two halves of forty-five minutes each

4. ___F___ There is no break in a football match

5. ___F___ Each football team has eleven players and a goal-keeper in the field

6. ___T___ The winning team in the match is the team which scores more goals

Ta có:

\(\frac{abc}{1000}=\frac{1}{a+b+c}\)

\(\frac{abc}{1000}=\frac{abc}{\left(a+b+c\right)abc}\)

-->(a+b+c)abc=1000

Ta có:

1000=10.100=100.10(loại vì a khác b khác c khác 0)

1000=5.200=200.5(loại vì a khác b khác c khác 0)

1000=2.500=500.2(loại vì a khác b khác c khác 0)

1000=4.250(loại vì a khác b khác c khác 0)

1000=8.125(chọn)

-->(a+b+c)abc=1000

-->a=1,b=2,c=5

     a+b+c=8 (chọn)

Thử lại:

0,125=\(\frac{1}{1+2+5}\)

Vậy abc=125

Mình giải không hay lắm nhỉ,nhưng cứ cho ****!