NT:(2x+1)^4>=0.Dấu ''='' xảy ra khi x=-1/2

=>(2x+1)^4-1>=-1.Dấu"=" xẩy ra khi x=-1/2

Vậy Min của biểu thức trên là -1

Read the following passage and mark the letter A, B, C, or D to indicate the correct word for each of the blanks from (1) to (10).

PROACTIVE JOB HUNTING

Once upon a time, people left school or university, joined a company and stayed with it until they retired. The concept of a job for life is now long (1) x , and nowadays many employees find it hard o stay loyal to their companies for even a relatively short period of time. According to a recent survey, this is particularly (2) x in London, where more than half of those asked said that they constantly (3) x one eye on other job opportunities, (4) x they are fairly happy in their existing job. A high number of London workers say that they are always on the (5) x , although they are content and motivated in their current position.

Job seekers find that the internet (6) x them with a quick and easy way to find out what's available, and 53 percent said that they had applied for a job or registered with an employment agency inthe past 12 months. This proactive (7) x means that people can look for a perfect job match with the (8) x of effort. But while this is good for job hunters, the growing lack of company loyalty could (9) x up being a big problem for employers .Perhaps surprisingly, the (10) x factors attracting job seekers was not more money, but challenging and interesting work.Question 5

A. search

B. pursuit

C. lookout

D. watch

Có thể phân biệt HCOOCH₃ và CH₃COOC₂H₅ bằng: 

A. AgNO₃ 

B. CaCO₃

C. H₂O

D. dung dịch Br₂ 

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. vocabulary

B. politically

C. documentary

D. laboratory

gọi AB là a;AC là b

ta có : a/5=b/12

suy ra: a=5k;b=12k

Áp dụng định lý Pitago vào tam giác ABC vuông tại A,có:

a^2+b^2=BC^2=[5k]^2+[12k]^2=676

=25k+144k=169k=676

suy ra:k=676:169=4

suy ra : a^2 =4*25=100[a= căn của 100]

b tương tự

tự KL nhé bạn