Cho bất phương trình 2 m 2 x + 10 − mx < 4 . Tìm m để bất phương trình có nghiệm x = − 3 .  

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 30 to 37.

  Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds – any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede farming. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight, nutrients, and water with useful plants.

The global need for weed control had been answered mainly by the chemical industry. Its herbicides are effective and sometimes necessary, but some pose serious problems, particularly if misused. Toxic compounds threaten animal and public health when they accumulate in food plants, groundwater, and drinking water. They also harm workers who apply them.

  In recent years, the chemical industry has introduced several herbicides that are more ecologically sound. Yet new chemicals alone cannot solve the world’s weed problems. Hence, scientists are exploring the innate weed-killing powers of living organisms, primarily insects and microorganisms.

The biological agents now in use are environmentally benign and are harmless to humans. They can be chosen for their ability to attack selected targets and leave crops and other plants untouched. In contrast, some of the most effective chemicals kill virtually all the plants they come in contact with, sparing only those that are naturally resistant or have been genetically modified for resistance. Furthermore, a number of biological agents can be administered only once, after which no added applications are needed. Chemicals typically must be used several times per growing season.

The word ‘applications’ in bold could best be replaced by which of the following?

A. treatments

B. requests

C. special purposes

D. qualifications

Ứng với công thức C_5­H₁₀O có bao nhiêu dông phân xeton

A. 2                        

B. 3             

C. 4                      

D. 5

Số tiền bạn An thu chi trong một ngày (đơn vị nghìn đồng) như sau: +100; -25; -30; +7. Đầu ngày trong két có +500 nghìn đồng. Hỏi cuối ngày trong két có bao nhiêu ?

Mark the letter A, B, C, or D on your answer sheet to indicate the word(s) CLOSEST in meaning to the underlined word(s) in each of the following questions.

Nobody owned up to breaking the window.

A. objected to

B. decided on

C. confessed to

D. allowed for

Mark the letter A, B, C, or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions

A. solutions

B. hospitals

C. families

D. projects 

CH₃CHO khi phản ứng với dd AgNO₃/NH₃ thu được muối B là

A. (NH₄)₂CO₃      

B. CH₃COONH₄   

C. CH₃COOAg     

D. NH₄NO₃

Hỗn hợp khí X gồm etilen, metan, propin và viyl axetilen có tỉ khối so với H₂ là 17. Đốt cháy hoàn toàn 0,05 ml hỗn hợp X rồi hấp thụ toàn bộ sản phẩm cháy vào bình đựng dung dịch Ca(OH)₂ (dư) thì khối lượng bình tăng thêm m gam. Giá trị của m là

A.5,85 

B. 3,39 

C. 6,60 

D. 7,30

___________ hard I have ever worked, I do not get good salary.

A. If 

B. Provided that

C. Nevertheless

D. However

Mark the letter A, B, C, or D on your answer sheet to indicate the word that differs from the other three in the position of primary stress in each of the following questions.

A. importance

B. happiness

C. employment

D. relation