giải pt

a).4x²+\(\dfrac{1}{x^2}\)+\(\left|2x-\dfrac{1}{x}\right|-6=0\)

b)\(4x^4+\left|2x^3-x\right|6x^2+1=0\)

^{c)\(\dfrac{x^2-1}{\left|x\right|\left(x-2\right)}=2\)}

Hiện nay, An 8 tuổi và chị Mai 28 tuổi. Sau bao nhiêu năm nữa thì 1/3 tuổi An bằng 1/7 tuổi chị Mai ?

Nguyên nhân sâu xa gây nên tình trạng mất ổn định của khu vực Tây Nam Á là

A. dầu mỏ và vị trí địa chính trị quan trọng

B. tôn giáo và các thế lực thù địch chống phá

C. xung đột dai dẳng giữa người Ả- rập và người Do Thái

D. tranh giành đất đai và nguồn nước

 Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 1 to 7.

Imagine the busy streets of New York City, an enormous place with millions of people. Everyday, the streets are congested with people going about their daily lives. Now imagine a small robot in the middle of all of those people rolling down a busy sidewalk. Most people would not even notice the ten–inch smiling robot, called a Tweenbot, rolling along the street. This strange machine may interest some people, while others would ignore it completely. A researcher interested in studying how helpful people really are uses such robots in her experiments that take place on the streets of New York.

The Tweenbots experiment is the idea and creation of Kacie Kinzer. Kinzer’s idea was to make a robot that could navigate the cityand reach its destination only if it was aided by pedestrians. Tweenbots rely on the kindnessof warm–hearted strangers. Made simply of cardboard, wheels, and a device to turn thewheels, the Tweenbots face many dangers on the city streets. They could be run over by cars or smashed by careless kids. Kinzer thought her little robots might even be seen as some kind of terrorist device. The only real protection a Tweenbot has is its friendly smile. In addition to that, each of Kinzer’s robots is fitted with a flag that displays instructions for the robot’s destination. The only way these robots will reach their final point is if someone lends them a hand. Tweenbots are essentially a social experiment aimed at providing people a chance toshow how caring they are.

On a daily basis, people in New York City are often in a hurry to get around. However, the Tweenbots, through their inability to look after themselves, took people out of their normal routines. The people who noticed the helpless little robots were actually interested in helping the Tweenbots find their way home. Tweenbots move at a constant speed and can only go in a straight line. If one was to get stuck, or was going in the wrong direction, it would be up to strangers to free it or turn it in the right direction. Surprisingly, no Tweenbot was lost or damaged, and each one arrived at its target in good condition. In fact, most people treated the robot in a gentle manner, and some even treated it as though it were a small living being.

Even if you were in a rush to go somewhere, would you stop and help a Tweenbot successfully reach its destination?

What is a Tweenbot?

A. A person from New York City 

B. A ten–inch smiling robot 

C. A pedestrian 

D. A terrorist device 

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 43 to 47. Fill in the appropriate word in question 45

THE GENERATION GAP

People talk about the generation gap as a kind of division between young people and their parents. It is something which is generally a problem when children enter their teenage years, and results (43)______ complaints on both side. Parents, for example, can often be heard to say that young people are (44)______ and disobedient and in addition tend to be irresponsible when spending because they don’t appreciate the (45)______ of money. Adolescents, on the other hand, complain that their parents don’t understand them.

What has gone wrong? One explanation lies in (46) ______society has changed. In the past, children would typically continue the way of life of their parents. In today’s world, parents are very (47) ______ for their children because they want them to achieve more than they did. The problem is that the children often don’t agree with their parents’ plans. Teenagers also reach maturity at an earlier age than they used to and want their independence sooner. The resulting conflict is painful to

both sides.  

Adapted form Mastering Use of English

A. worth

B. value

C. cost

D. amount

Khi đốt cháy hoàn toàn một hợp chất hữu cơ thu được hỗn hợp khí CO2 và hơi nước có tỉ lệ mọt là 1:1. Chất này có thể lên men rượu. Đó là chất nào trong số các chất dưới đây?

A. Axit axetic

B. Glucozơ

C. Saccarozơ

D. Fructozơ

Choose the correct sentence which has the same meaning as the given one

“You’d better think carefully before applying for that job.” She said to me

A. She said me to think carefully before applying for that job

B. She says me to think carefully before applying for that job

C. She advise me to think carefully before applying for that job

D. She advised me to think carefully before applying that job

Ở cà chua, alen A quy định quả màu đỏ là trội hoàn toàn so với alen a quy định quả màu vàng, alen B quy định thân cao là trội hoàn toàn so với alen b quy định thân thấp. Cho cây tứ bội có kiểu gen AAaaBBBb tự thụ phấn thu được F₁. Trong số cây thân cao, quả đỏ ở F₁, tỉ lệ cây F₁ khi tự thụ phấn cho tất cả các hạt khi đem gieo đều mọc thành cây thân cao, quả đỏ là bao nhiêu? Biết hai cặp gen nói trên phân li độc lập, quá trình giảm phân bình thường và không xảy ra đột biến.

A. 0,71%.

B. 19,29%.

C. 18,75%.

D. 17,14%.

  z - 3 + 4 i = 2 , w   = 2 z + 1 - i  Khi đó |w| có giá trị lớn nhất là: