## Thống kê điểm hỏi đáp trong tuần qua. Nguyễn Công Tỉnh

Điểm hỏi đáp: 10100

 Ngày 18 - 11 Điểm 3

Tổng: 10100 | Điểm tuần: 3 | Trả lời 7 ngày qua: 0 | Lượt trả lời trong tháng: 1

Lượt trả lời trong 3 tháng: 195

#### Những câu trả lời của Nguyễn Công Tỉnh:

Vào lúc: 2019-11-04 21:59:14 Xem câu hỏi

có chuyện gì zậy :>>>

Vào lúc: 2019-10-17 22:15:31 Xem câu hỏi

$$P=\frac{4}{3}\Rightarrow\frac{\sqrt{x}+2}{\sqrt{x}+1}=\frac{4}{3}$$

$$\Leftrightarrow3\left(\sqrt{x}+2\right)=4\left(\sqrt{x}+1\right)$$

$$\Leftrightarrow3\sqrt{x}+6=4\sqrt{x}+4$$

$$\Leftrightarrow6-4=4\sqrt{x}-3\sqrt{x}$$

$$\Leftrightarrow\sqrt{x}=2\Leftrightarrow x=4$$(ko thỏa mãn ĐKXĐ)

=>pt vo nghiệm

d,$$\left(\sqrt{x}+1\right)P-\sqrt{x}-4\sqrt{x-1}+26=-6x+10\sqrt{5x}$$

$$\Leftrightarrow\left(\sqrt{x}+1\right)\frac{\sqrt{x}+2}{\sqrt{x}+1}-\sqrt{x}-4\sqrt{x-1}+26=-6x+10\sqrt{5x}$$

$$\Leftrightarrow\sqrt{x}+2-\sqrt{x}-4\sqrt{x-1}+26=-6x+10\sqrt{5x}$$

$$\Leftrightarrow-4\sqrt{x-1}+28=-6x+10\sqrt{5x}$$

$$\Leftrightarrow x=5$$

Vào lúc: 2019-10-17 22:10:07 Xem câu hỏi

$$a,x=7-4\sqrt{3}=4-2.2\sqrt{3}+3$$ (Thỏa mãn ĐKXĐ)

$$=\left(2-\sqrt{3}\right)^2$$

$$B=\frac{2}{\sqrt{x}-2}=\frac{2}{\sqrt{\left(2-\sqrt{3}\right)^2}-2}$$

$$=\frac{2}{2-\sqrt{3}-2}=-\frac{2\sqrt{3}}{3}$$

$$b,P=\frac{B}{A}=\frac{2}{\sqrt{x}-2}:\left(\frac{\sqrt{x}}{x-4}+\frac{1}{\sqrt{x}-2}\right)$$

$$=\frac{2}{\sqrt{x}-2}:\left(\frac{\sqrt{x}}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}+\frac{\sqrt{x}+2}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}\right)$$

$$=\frac{2}{\sqrt{x}-2}:\frac{\sqrt{x}+\sqrt{x}+2}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}$$

$$=\frac{2}{\sqrt{x}-2}:\frac{2\sqrt{x}+2}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}$$

$$=\frac{2}{\sqrt{x}-2}.\frac{\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)}{2\left(\sqrt{x}+1\right)}$$

$$=\frac{\sqrt{x}+2}{\sqrt{x}+1}$$

Vào lúc: 2019-10-17 21:55:35 Xem câu hỏi

$$\hept{\begin{cases}x^2+y^2=5\\x^3+2y^2=10x-10y\end{cases}}$$

$$\Leftrightarrow\hept{\begin{cases}x=\sqrt{5-y^2}\\\left(\sqrt{5-y^2}\right)^3+2y^2=10\sqrt{5-y^2}-10y\end{cases}}$$

$$\Leftrightarrow\hept{\begin{cases}x=\sqrt{5-y^2}\\y=1\end{cases}}$$

$$\Leftrightarrow\hept{\begin{cases}x=\sqrt{5-1^2}=\sqrt{4}=2\\y=1\end{cases}}$$

$$\Leftrightarrow\hept{\begin{cases}x=2\\y=1\end{cases}}$$

Vào lúc: 2019-10-17 21:49:22 Xem câu hỏi

$$1,P=\frac{x+2}{x\sqrt{x}-1}+\frac{\sqrt{x}+1}{x+\sqrt{x}+1}-\frac{\sqrt{x}+1}{x-1}$$

$$=\frac{x+2}{x\sqrt{x}-1}+\frac{\sqrt{x}+1}{\left(x+\sqrt{x}+1\right)}-\frac{\sqrt{x}+1}{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}$$

$$=\frac{x+2}{x\sqrt{x}-1}+\frac{\sqrt{x}+1}{\left(x+\sqrt{x}+1\right)}-\frac{1}{\sqrt{x}-1}$$

$$=\frac{x+2}{x\sqrt{x}-1}+\frac{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}{\left(x+\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}-\frac{x+\sqrt{x}+1}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}$$

$$=\frac{x+2+x-1-x-\sqrt{x}-1}{x\sqrt{x}-1}$$

$$=\frac{x-\sqrt{x}}{x\sqrt{x}-1}$$

$$=\frac{\sqrt{x}\left(\sqrt{x}-1\right)}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}$$

$$=\frac{\sqrt{x}}{x+\sqrt{x}+1}$$

Vào lúc: 2019-10-17 21:44:25 Xem câu hỏi

$$C=-A.B=-\frac{x+\sqrt{x}+1}{\sqrt{x}+1}\cdot\frac{-\sqrt{x}}{x+\sqrt{x}+1}=\frac{\sqrt{x}}{\sqrt{x}+1}$$

$$=\frac{\sqrt{x}+1-1}{\sqrt{x}+1}=1-\frac{1}{\sqrt{x}+1}$$

$$ĐểC\in Z\Rightarrow\frac{1}{\sqrt{x}+1}\in Z$$

$$\Rightarrow\sqrt{x}+1\in\left\{1\right\}=\left\{1;-1\right\}$$

$$\Leftrightarrow x\in\left\{0\right\}$$

Kết hợp ĐKXĐ =>...

Vào lúc: 2019-10-17 19:39:42 Xem câu hỏi

$$A=\frac{x+\sqrt{x}+1}{\sqrt{x}+1}ĐKXĐ:x\ge0$$

$$\Rightarrow A=\frac{2+\sqrt{2}+1}{\sqrt{2}+1}=\frac{3+\sqrt{2}}{1+\sqrt{2}}=2\sqrt{2}-1$$

$$B=\frac{1}{\sqrt{x}-1}-\frac{x+2}{x\sqrt{x}-1}-\frac{\sqrt{x}+1}{x+\sqrt{x}+1}$$

$$=\frac{x+\sqrt{x}+1}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}-\frac{x+2}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}-\frac{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}$$

$$=\frac{x+\sqrt{x}+1-x-2-x+1}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}$$

$$=\frac{\sqrt{x}-x}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}$$

$$=\frac{\left(1-\sqrt{x}\right)\sqrt{x}}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}$$

$$=\frac{-\sqrt{x}}{x+\sqrt{x}+1}$$

Vào lúc: 2019-10-17 19:16:41 Xem câu hỏi

$$Q=\frac{2P\sqrt{x}}{3}=\frac{2\left(\frac{3}{\sqrt{x}+3}\right)\sqrt{x}}{3}=\frac{6\sqrt{x}}{\sqrt{x}+3}\cdot\frac{1}{3}$$

$$=\frac{2\sqrt{x}}{\sqrt{x}+3}=\frac{2\sqrt{x}+6-6}{\sqrt{x}+3}=\frac{2\left(\sqrt{x}+3\right)}{\sqrt{x}+3}-\frac{6}{\sqrt{x}+3}$$

$$=2-\frac{6}{\sqrt{x}+3}$$

$$ĐểQ\in Z\Rightarrow\frac{6}{\sqrt{x}+3}\in Z$$

$$\Rightarrow\sqrt{x}+3\inƯ\left(6\right)=\left\{1;2;3;6;-1;-2;-3;-6\right\}$$

$$\Rightarrow\sqrt{x}\in\left\{-2;-1;0;3\right\}$$

$$\Rightarrow x\in\left\{0;9\right\}$$

Kết hợp ĐKXĐ $$\Rightarrow x=0$$

Vào lúc: 2019-10-17 19:10:50 Xem câu hỏi

$$b,x=20-6\sqrt{11}=11-2.3\sqrt{11}+9$$

$$=\left(\sqrt{11}-3\right)^2$$

$$P=\frac{3}{\sqrt{x}+3}=\frac{3}{\sqrt{\left(\sqrt{11}-3\right)^2}+3}=\frac{3}{\sqrt{11}-3+3}=\frac{3\sqrt{11}}{11}$$

$$c,P>\frac{1}{2}\Rightarrow\frac{3}{\sqrt{x}+3}>\frac{1}{2}$$

$$\Leftrightarrow\frac{3}{\sqrt{x}+3}-\frac{1}{2}>0$$

$$\Leftrightarrow\frac{6-\sqrt{x}-3}{2\left(\sqrt{x}+3\right)}>0$$

$$\Leftrightarrow\frac{6-\sqrt{x}-3}{2\left(\sqrt{x}+3\right)}>0$$$$\Leftrightarrow\frac{3-\sqrt{x}}{2\left(\sqrt{x}+3\right)}>0$$

vì $$2\left(\sqrt{x}+3\right)>0$$ (nếu x=0 =>pt vô nghiệm)

$$\Rightarrow3-\sqrt{x}>0\Rightarrow\sqrt{x}< 3\Rightarrow x< 9$$

Kết hợp ĐKXĐ: $$0< x< 9$$

Vào lúc: 2019-10-17 18:48:01 Xem câu hỏi

$$P=\left(\frac{3x+3}{x-9}-\frac{2\sqrt{x}}{\sqrt{x}+3}+\frac{\sqrt{x}}{3-\sqrt{x}}\right):\left(\frac{2\sqrt{x}-2}{\sqrt{x}-3}-1\right).ĐKXĐ:x\ge0,x\ne9$$

$$=\left(\frac{3x+3}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}-\frac{2\sqrt{x}\left(\sqrt{x}-3\right)}{\left(\sqrt{x}+3\right)\left(\sqrt{x}-3\right)}-\frac{\sqrt{x}\left(\sqrt{x}+3\right)}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}\right):\left(\frac{2\sqrt{x}-2}{\sqrt{x}-3}-1\right)$$

$$=\left(\frac{3x+3-2x+6\sqrt{x}-x-3\sqrt{x}}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}\right):\left(\frac{2\sqrt{x}-2-\sqrt{x}+3}{\sqrt{x}-3}\right)$$

$$=\frac{3\sqrt{x}+3}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}:\frac{\sqrt{x}+1}{\sqrt{x}-3}$$

$$=\frac{3\left(\sqrt{x}+1\right)}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}.\frac{\sqrt{x}-3}{\sqrt{x}+1}$$

$$=\frac{3}{\sqrt{x}+3}$$

Vào lúc: 2019-10-17 18:36:09 Xem câu hỏi

Complete the second so that it has similar meaning to the first sentence:

1.Tom started recycling rubbish two years ago

Tom has....................recycled rubbish for two years......................

2.We have donated books and clothes for ten years

We began.................donating books and clothes ten years ago................

3.The last time we saw her was on Christmas Day.

We haven't................ seen her since Christmas Day................

4.I haven't eaten this kind of food before.

This is..........the first time I have eaten this kind of food........................

5.It started raiing an hour ago

It has........rained for an hour..................

Vào lúc: 2019-10-17 18:34:19 Xem câu hỏi

There is a mistake in each of these sentences.Underline the mistake and then correct it

1.It has started craining an hour ago

...........=>started.....................................................

2.I knew Hoa for some months.

..........have known...................................

3.We didn't see Nga since Monday

..........=>haven't seen....................................

4.Minh was in the USA for 2 years

.............=>has been..........................

5.I have gone to bed ai 10 o'clock last night

............=>went.............................................

6.They moved to London for 2003

..........have moved ; since...................................

7.How long have you learn English?

............=>learnt........................

8.Peter was ill for a week.

............=>has been.............................

Vào lúc: 2019-10-17 18:31:51 Xem câu hỏi

Use the suggestions to write sentences of comparative

=>Your brother is more optimis than you

2.Air/countryside/heathy/city

=>The air in the countryside is healthier than The air in the city

3.People/countryside/work/hard/city

=>People in the countryside work harder than People in the city

=>A cow ploughs worse than a buffalo

6.Mai/speak English/fluent/her sister

=>Mai speaks E more fluently than her sister does

7.Summer/hot/autumn

=>Summer is hotter than autumn

8.Life/countryside/peaceful/city

=>Life in the countryside is more peaceful than life in the city

9.An ox/strong/a horse

=>An ox is stronger than a horse

10.Quang/write/careful/his friends

=>Quang writes more carefully than his friends do

Vào lúc: 2019-10-17 18:30:30 Xem câu hỏi

Khoanh những từ được gạch chân có phát âm riêng biệt:
1) A. biscuit     B. cat     C. occasion     D. check
2) A. sugar     B. green     C. guitar     D. good
3) A. black     B. back     C. chemist     D. goft
4) A. great     B. again     C. character     D. garden
5) A. naked     B. wanted     C. needed     D. watched
6) A. polluted     B. looked     C. washed     D. laughed
7) A. washes     B. houses     C. places     D. likes
8) A. foot     B. first     C. of     D. friday
9) A. famous     B. shirt     C. about     D. family
10) A. turn     B. surpose     C. church     D. her
Có vài câu khá vô lí

Vào lúc: 2019-10-16 21:44:37 Xem câu hỏi

Circle the word that is pronounced differently from the others.

 1. bear leave peace cheap 2. near here ear meat 3. hair chair rain air 4. tour pour four thought 5. gulf hunt sure ourrent 6. where share wear fear 7. cheer feed deep sea 8. pear clear sphere idea 9. heir dear their care 10. group souvenir through should

II. Complete the sentences with the correct form of the words in the box.

 challenge       discover       depend        investigate        contributecover            conserve       entrap         maintain           mystery

1. Scientists have made many important new……discoveries………..of the depth by using modern devices.

2. Community police have made a very positive……… contribution…..to crime prevention.

4. They are investigating the……mysterious………..disappearance of a young woman.

5. Seventy-five percent of the earth surface is……covered………..by water.

6. The power station has been shut down for essential……maintenance………..

7. The………investigation……..of the seabed is being carried out.

8. Sperm whale populations are at risk due to hunting and their accidental…………entrapment…. in fishing nets.

9. By the age of eighteen he was complete………independent……..of his parents.

10. The government has just set up a wildlife………conservation……..project.

Vào lúc: 2019-10-16 21:42:03 Xem câu hỏi

1,Choose the word which has the underlined part pronounced differently from others by circling A,B,C orD

1.Abed              B.clocks                     C.walls                        D.tables

2.A.grandparents                 B. brothers               C.uncles                           D.fathers

3.A.mother                    B. centers                       C.aunts                            D.cousins

4.A.cities                         B.watches                       C. dishes                         D. houses

5.A.books                B.rooms                     C.wall                           D. pillows

Vào lúc: 2019-10-16 21:40:55 Xem câu hỏi

I/ Circle the word that has the underlined part pronounced differently from the others.
1. A. answer  B. teacher  C. butter  D. birth
2. A. surprise             B. alone  C. neighbour            D. burn
3. A. of  B. fat   C. few             D. safe
4. A. sping  B. visit              C. present  D. usually
5. A. school  B. keen  C. city              D. cook
6.       A. fun                      B. run                               C. music                          D. sun
7.       A. wanted               B. played                          C. donated                       D. provided
8.       A. celeation         B. collection                     C. education                   D. question
9.      A. who                     B. what                             C. why                            D.   when

Vào lúc: 2019-10-16 21:37:57 Xem câu hỏi

Câu bị động

1. Nga does these exercises quickly.

=>these exercises are done quickly by Nga

2. they have to pay the bill before the first of the month.

=> the bill has to be paid before the first of the month.

3. they will ask you some questions.

=>You will be asked some questions.

4. Somebody has locked the box and I can't open it.

=>the box has been locked  and I can't open it.

5. I am doing this work now.

=>This work is being done by me now

6. the boys has painted this wall for 2 days.

=>This wall has been painted by the boys for 2 days.

7. Someone will collect the paper from the room.

=>the paper will be collected from the room.

8. the students were keeping the food in the boxes when we came.

=>the food was being kept in the boxes when we came.

Vào lúc: 2019-10-16 21:35:45 Xem câu hỏi

Ex4: Viết lại các câu sau sao cho nghĩa ko đổi:

1, Lan is taller than Hoa->hoa is.......shorter than Lan.......

2, I am bigger than my sister->my sister is.......smaller than I.........

3,Jane cooks better than me->i cook......worse than Jane...........

4, My mom ís younger than my dad->my dad is.....older than my mom.........

5, Nam is thinner Minh->Minh is.......fatter than Nam........

6, My father is heavier than me->i am........lighter than my father............

7, That tree ís higher than this tree->this tree is.........shorter that tree.....

8, My shirt ó older than your shirrt-> your shirt is........younger than my sister.....

Ex5: Viết câu so sánh sử dụng các tính từ:

vd: i/thin/my brother->. i am thinner than brother

1. A  lake is larger than a sea->.................

2. This book is better than that one->................

3.the weather here is hotter than the weather in my hometown->

4 a mouse is smaller than a cat->

5 the sun is bigger than the moon->

6 a radio is cheaper than a television->

7 a child is younger than a man->

8 a mountain is higher than a hill

Vào lúc: 2019-10-16 21:32:54 Xem câu hỏi

Ex1:Viết thành câu hoàn chỉnh, sử dụng tính từ so sánh

A new house is___more expensive than_ an old house. (expensive)

Motorbikes are __faster than__ bikes. (fast)

My television is ___more mordern than__ his television. (modern)

Summer is __hotter than__ spring. (hot)

Jane is __more beautiful than__ her sister.(beautiful)

Skirts are __more cheaper than__ dresses. (cheap)

Her English is _better than_ my English. (good)

Ex2: Dùng so sánh hơn để viết những câu sau:

1- my school is bigger than your school

2- Lan is younger than Hoa

3- my father is older than my mother

4-this ruler is longer than that ruler

5- this room is larger than my room

6-the boys are stronger than the girl

7-my house is taller than your house

8- Nam is shorter than his sister

Ex3: Cho dạng so sánh đúng của tính từ trong ngoặc;

1-Rivers are (big).......bigger....... than lakes.

2-The Mekong river is (long)....longer...........thatthe Red river.

3-My mother is (old).....older...... than my teacher

4-Nga and Lan are (short).......shorter........than Minh

5-My mother is(young)......younger..........than my father

6-Ha Noi is (small) .....smaller........... than Ho Chi Minh city

7-This boy is(tall) ......taller.........than that boy

8-A dictionary is (thick)....thicker....... than a notebook

9-Buildings are (high) .........higher............ than houses