x²+1/x²+x+1/x=4

cho phương trình x²+mx-5=0.tìm giá trị của m để tổng bình phương của phương trình là 11

cho phương trình 3mx² +2(2m+1)x+m=0 . Xác định m để phương trình co 2 nghiệm âm

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

Scientists do not yet thoroughly understand just how the body of an individual becomes sensitive to a substance that is harmless or even wholesome for the average person. Milk, wheat, and egg, for example, rank among the most healthful and widely used foods. Yet these foods can cause persons sensitive to them to suffer greatly. At first, the body of the individual is not harmed by coming into contact with the substance. After a varying interval of time, usually longer than a few weeks, the body becomes sensitive to it, and an allergy has begun to develop. Sometimes it's hard to figure out if you have a food allergy, since it can show up so many different ways. Your symptoms could be caused by many other problems. You may have rashes, hives, joint pains mimicking arthritis, headaches, irritability, or depression. The most common food allergies are to milk, eggs, seafood, wheat, nuts, seeds, chocolate, oranges, and tomatoes. Many of these allergies will not develop if these foods are not fed to an infant until her or his intestines mature at around seven months. Breast milk also tends to be protective. Migraines can be set off by foods containing tyramine, phenathylamine, monosodium glutamate, or sodium nitrate. Common foods which contain these are chocolate, aged cheeses, sour cream, red wine, pickled herring, chicken livers, avocados, ripe bananas, cured meats, many Oriental and prepared foods (read the labels!). Some people have been successful in treating their migraines with supplements of B-vitamins, particularly B6 and niacin. Children who are hyperactive may benefit from eliminating food additives, especially colorings, and foods high in salicylates from their diets. A few of these are almonds, green peppers, peaches, tea, grapes. This is the diet made popular by Benjamin Feingold, who has written the book “Why your Child is Hyperactive”. Other researchers have had mixed results when testing whether the diet is effective.

The word "symptoms" is closest in meaning to ___________.

A. prescriptions

B. diet

C. diagnosis

D. indication

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

Scientists do not yet thoroughly understand just how the body of an individual becomes sensitive to a substance that is harmless or even wholesome for the average person. Milk, wheat, and egg, for example, rank among the most healthful and widely used foods. Yet these foods can cause persons sensitive to them to suffer greatly. At first, the body of the individual is not harmed by coming into contact with the substance. After a varying interval of time, usually longer than a few weeks, the body becomes sensitive to it, and an allergy has begun to develop. Sometimes it's hard to figure out if you have a food allergy, since it can show up so many different ways. Your symptoms could be caused by many other problems. You may have rashes, hives, joint pains mimicking arthritis, headaches, irritability, or depression. The most common food allergies are to milk, eggs, seafood, wheat, nuts, seeds, chocolate, oranges, and tomatoes. Many of these allergies will not develop if these foods are not fed to an infant until her or his intestines mature at around seven months. Breast milk also tends to be protective. Migraines can be set off by foods containing tyramine, phenathylamine, monosodium glutamate, or sodium nitrate. Common foods which contain these are chocolate, aged cheeses, sour cream, red wine, pickled herring, chicken livers, avocados, ripe bananas, cured meats, many Oriental and prepared foods (read the labels!). Some people have been successful in treating their migraines with supplements of B-vitamins, particularly B6 and niacin. Children who are hyperactive may benefit from eliminating food additives, especially colorings, and foods high in salicylates from their diets. A few of these are almonds, green peppers, peaches, tea, grapes. This is the diet made popular by Benjamin Feingold, who has written the book “Why your Child is Hyperactive”. Other researchers have had mixed results when testing whether the diet is effective.

According to the passage, the difficulty in diagnosing allergies to foods is due to ___________.

A. the vast number of different foods we eat

B. lack of a proper treatment plan

C. the similarity of symptoms of the allergy to other problems

D. the use of prepared formula to feed babies

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

Scientists do not yet thoroughly understand just how the body of an individual becomes sensitive to a substance that is harmless or even wholesome for the average person. Milk, wheat, and egg, for example, rank among the most healthful and widely used foods. Yet these foods can cause persons sensitive to them to suffer greatly. At first, the body of the individual is not harmed by coming into contact with the substance. After a varying interval of time, usually longer than a few weeks, the body becomes sensitive to it, and an allergy has begun to develop. Sometimes it's hard to figure out if you have a food allergy, since it can show up so many different ways. Your symptoms could be caused by many other problems. You may have rashes, hives, joint pains mimicking arthritis, headaches, irritability, or depression. The most common food allergies are to milk, eggs, seafood, wheat, nuts, seeds, chocolate, oranges, and tomatoes. Many of these allergies will not develop if these foods are not fed to an infant until her or his intestines mature at around seven months. Breast milk also tends to be protective. Migraines can be set off by foods containing tyramine, phenathylamine, monosodium glutamate, or sodium nitrate. Common foods which contain these are chocolate, aged cheeses, sour cream, red wine, pickled herring, chicken livers, avocados, ripe bananas, cured meats, many Oriental and prepared foods (read the labels!). Some people have been successful in treating their migraines with supplements of B-vitamins, particularly B6 and niacin. Children who are hyperactive may benefit from eliminating food additives, especially colorings, and foods high in salicylates from their diets. A few of these are almonds, green peppers, peaches, tea, grapes. This is the diet made popular by Benjamin Feingold, who has written the book “Why your Child is Hyperactive”. Other researchers have had mixed results when testing whether the diet is effective.

The topic of this passage is _____________.

A. infants and allergies

B. food and nutrition

C. reactions to foods

D. a good diet

Mark the letter A,B,C or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions.

My sister told me that she had met my teacher at the supermarket yesterday.

A.My sister told

B.she had met

C.at the supermarket

D.yesterday.

Mark the letter A,B,C or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions.

On the floor of the Pacific Ocean is hundreds of flat-topped mountains more than a mile beneath sea level.

A. On

B.is

C.hundreds of

D.more than

Read the following passage and choose the best answer for each blank.

      Young children are increasingly using tablets as well as smartphones and other devices with touch screens in early education (1) ______ and with family members.

       Tammy and Rose, age 4 have been studying sunflowers with their classmates. They want to sing and record a song about sunflowers while creating a drawing, using a(n) (2) _______ on the tablet. The girls have coordinated their efforts and are happy with the result.

      To help the class learn more about sunflowers, Kathryn. Tammy and Rose’s teacher, used the tablet to find online (3)_______ with photos and facts. She then took the children on (4) _______ a tour of Van Gogh’s sunflower paintings. They read and discussed an electronic picture book about Van Gogh’s life. The children had already examined real sunflowers and their parts, made sketches, read informational texts and stories, counted seeds, and (5) _______ part in a variety of investigations, touching on every learning domain. The teacher’s use of the tablet together with early practical learning activities expanded the children's (6) _______. Activities offered on the tablet provided new (7) _______for the children to represent and share what they learned.

     Tablets have the (8) _______to be powerful tools for early learning. The choices we make about how they are used determine (9) _______ the technology is helpful or not. We need to develop “digital literacy” skills and decide how to use these new tools in ways (10) _______ can support every child’s healthy development and learning.

The teacher’s use of the tablet together with early practical learning activities expanded the children's (6) _______.

A. distances

B. skies

C. lessons

D. horizon

Choose the best answer.

_________ alone. It's very dangerous.

A. Travel 

B. Do travel 

C. Don't travel 

D. Travelling