\(B=\dfrac{1}{\sqrt{1}}+\dfrac{1}{\sqrt{2}}+\dfrac{1}{\sqrt{3}}+...+\dfrac{1}{\sqrt{47}}+\dfrac{1}{\sqrt{48}}\). CMR: B > 12

Giải phương trình:

\(\dfrac{2+\sqrt{x}}{\sqrt{2}+\sqrt{2+\sqrt{x}}}+\dfrac{2-\sqrt{x}}{\sqrt{2}-\sqrt{2-\sqrt{x}}}=\sqrt{2}\)

Để m(g) bột sắt (A) ngoài không khí, sau một thời gian biến thành hỗn hợp (B) có khối lượng 12g gồm Fe, FeO, Fe₃O₄, Fe₂O₃. Cho B tác dụng hoàn toàn với dung dịch HNO₃, thấy sinh ra 2,24 lít khí NO duy nhất ở đktc. Tính m.

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 25 to 29.

     The knock-on effect of volunteering on the lives of individuals can be profound. Voluntary work helps foster independence and imparts the ability to deal with different situations, often simultaneously, thus teaching people how to (25)______ their way through different systems. It therefore brings people into touch with the real world; and, hence, equips them for the future.

     Initially, young adults in their late teens might not seem to have the expertise or knowledge to impart to others that say a teacher or an agriculturalist or a nurse would have, (26) ______ they do have many skills that can help others. And in the absence of any particular talent, their energy and enthusiasm can be harnessed for the benefit (27) ______ their fellow human beings, and ultimately themselves. From all this, the gain to any community no matter how many volunteers are involved is (28) ______.

     Employers will generally look favorably on people (29) ______ have shown an ability to work as part of a team. It demonstrates a willingness to learn and an independent spirit, which would be desirable qualities in any employee.

Điền vào ô số 28

A. impassable 

B. unattainable      

C. undetectable     

D. immeasurable 

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 25 to 29.

     The knock-on effect of volunteering on the lives of individuals can be profound. Voluntary work helps foster independence and imparts the ability to deal with different situations, often simultaneously, thus teaching people how to (25)______ their way through different systems. It therefore brings people into touch with the real world; and, hence, equips them for the future.

     Initially, young adults in their late teens might not seem to have the expertise or knowledge to impart to others that say a teacher or an agriculturalist or a nurse would have, (26) ______ they do have many skills that can help others. And in the absence of any particular talent, their energy and enthusiasm can be harnessed for the benefit (27) ______ their fellow human beings, and ultimately themselves. From all this, the gain to any community no matter how many volunteers are involved is (28) ______.

     Employers will generally look favorably on people (29) ______ have shown an ability to work as part of a team. It demonstrates a willingness to learn and an independent spirit, which would be desirable qualities in any employee.

Điền vào ô số 27

A. under     

B. of 

C. on  

D. out 

Ý nào sau đây không đúng khi nói về tác động của thị trường đến các mặt hàng công nghiệp nước ta hiện nay?

A. Thị trường trong nước khá rộng lớn

B. Sản phẩm bị cạnh tranh bởi các hàng ngoại nhập

C.Không thể xuất khẩu sang các nước công nghiệp phát triển

D. Còn hạn chế về mẫu mã, chất lượng sản