ta có \(p=\dfrac{n+2}{n-7}=\dfrac{n-7+9}{n-7}=1+\dfrac{9}{n-7}\)để p có gtln thì \(\dfrac{9}{n-7}\)phải có giá trị lớn nhất

khi đó \(\dfrac{9}{n-7}\) phải là phân số dương và n-7 phải có gí trị nhỏ nhất (mẫu càng nhỏ thì phân số càng lớn)

\(\Rightarrow n-7=1\Leftrightarrow n=1+7=8\) vậy P có gí trị lớn nhất khi n=8

bài 5

\(\dfrac{7n-8}{2n-3}\)=\(\dfrac{3\left(2n-3\right)+n+1}{2n-3}=3+\dfrac{n+1}{2n-3}\)để PS trên có gtrị lớn nhất thì \(\dfrac{n+1}{2n-3}lớn\) nhất mà \(\) khi đó 2n-3 nhỏ nhất và \(\dfrac{n+1}{2n-3}\) là PS dương khi đó 2n-3=1\(\Rightarrow2n=4\Rightarrow n=2\) vậy n= 2 thì PS trên đạt gtrị lớn nhất

Các chất trong dãy nào sau đây có khả năng tham gia phản ứng trùng hợp?

A. stiren, clobenzen.

B. 1,1,2,2-tetrafloeten, propilen.

C. etyl clorua, butađien-1,3.

D. 1,2-điclopropan, vinylaxetilen.

Kết luận nào sau đây đúng đối với cấu tạo của H₂S

A. Phân tử H₂S có 2 liên kết cộng hóa trị có cực

B. S trong phân tử H₂S lai hóa sp³

C. Phân tử H₂S có cấu tạo hình gấp khúc

D. Góc hóa trị HSH lớn hơn góc hóa trị HOH

Hãy nêu vai trò của nhà ở đối với đời sống con người

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 23 to 27.

Years ago, in their private family role, women quite often dominate the male members of the household. Women were quite (23)____ to their families. However, the public role of women has

changed (24)______since the beginning of World War II. During the war, men were away from

home to the battle. As a (25)_____women were in complete control of the home. They found

themselves doing double and sometimes triple duty. They began to take over the work of their
absent husbands and to work outside. They accounted for 73% of the industrial labor force.
Women were forced by economic realities to work in the factories. The women (26)______ worked there were paid low wages, lived in crowded and small dormitories. (27)______they found
themselves a place as active members of society.

(Source: haps://goo.91/aeawF4)

Question 24

A. unfortunately

B. approximately

C. nearly

D. dramatically

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 23 to 27.

Years ago, in their private family role, women quite often dominate the male members of the household. Women were quite (23)____ to their families. However, the public role of women has

changed (24)______since the beginning of World War II. During the war, men were away from

home to the battle. As a (25)_____women were in complete control of the home. They found

themselves doing double and sometimes triple duty. They began to take over the work of their
absent husbands and to work outside. They accounted for 73% of the industrial labor force.
Women were forced by economic realities to work in the factories. The women (26)______ worked there were paid low wages, lived in crowded and small dormitories. (27)______they found
themselves a place as active members of society.

(Source: haps://goo.91/aeawF4)

Question 23

A. fascinated

B. worried

C. dedicated

D. interested