Câu 36: A

Câu 37: D

Câu 38: C

Câu 39: C

Câu 40: B

Câu 41: D

thank bạn nhìu , không biết tí nx bạn còn online khum , nếu còn vô chỉ bài mình nha :3

37 He suggested that Sue buy that picture as an anniversary present for Jack

38 You know the man who sat next to me at the meeting last night, don't you?

39 Covid 19 prevented us from travelling to Da Lat

40 If I had much money, I could buy that house immediately

40 Ba suggested that face mask should be worn when going out in public.

37. If he weren't lazy, he wouldn't get bad marks.

38. The boys felt interested in the show.

39. My brother had the vet examined his pet dog last week.

40. Ba suggested that face mask should be worn when going out in public.

1.\(\frac{4}{3.7}+\frac{4}{7.11}+\frac{4}{11.15}+\frac{4}{15.19}+\frac{4}{19.23}+\frac{4}{23.27}\)

\(=\frac{1}{3}-\frac{1}{7}+\frac{1}{7}-\frac{1}{11}+...+\frac{4}{23}-\frac{4}{27}\)

\(=\frac{1}{3}-\frac{1}{27}=\frac{9}{27}-\frac{1}{27}=\frac{8}{27}\)

2. Đặt \(A=\frac{3}{14}+\frac{3}{84}+\frac{3}{204}+\frac{3}{374}+\frac{3}{594}+\frac{3}{864}\)

\(\Rightarrow A=\frac{3}{2.7}+\frac{3}{7.12}+...+\frac{3}{27.32}\)

\(\Rightarrow5A=3.\left(\frac{5}{2.7}+\frac{5}{7.12}+...+\frac{5}{27.32}\right)\)

\(\Rightarrow5A=3.\left(\frac{1}{2}-\frac{1}{7}+\frac{1}{7}-\frac{1}{12}+...+\frac{1}{27}-\frac{1}{32}\right)\)

\(\Rightarrow5A=3.\left(\frac{1}{2}-\frac{1}{32}\right)\)

\(\Rightarrow5A=3.\frac{15}{32}=\frac{45}{32}\Rightarrow A=\frac{45}{32}:5=\frac{9}{32}\)

3. Đặt \(S=\frac{1}{10}+\frac{1}{40}+\frac{1}{88}+...+\frac{1}{340}\)

\(\Rightarrow3S=\frac{3}{10}+\frac{3}{40}+...+\frac{3}{340}\)

\(\Rightarrow3S=\frac{3}{2.5}+\frac{3}{5.8}+...+\frac{3}{17.20}\)

\(\Rightarrow3S=\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+...+\frac{1}{17}-\frac{1}{20}\)

\(\Rightarrow3S=\frac{1}{2}-\frac{1}{20}=\frac{9}{20}\Rightarrow S=\frac{9}{20}:3=\frac{3}{20}\)

Câu 1:

\(\frac{4}{3.7}+\frac{4}{7.11}+\frac{4}{11.15}+\frac{4}{15.19}+\frac{4}{19.23}+\frac{4}{23.27}\)

\(\Rightarrow\frac{1}{3}-\frac{1}{7}+\frac{1}{7}-\frac{1}{11}+\frac{1}{11}-\frac{1}{15}+\frac{1}{15}-\frac{1}{19}+\frac{1}{19}-\frac{1}{23}+\frac{1}{23}-\frac{1}{27}\)

\(\Rightarrow\frac{1}{3}-\frac{1}{27}\)

\(=\frac{8}{27}\)

Câu 1: 

a:=17+5=22

b: =40-25=15

\(A=\frac{1}{2012}+\frac{37^{2012}}{2012^{38}}+\frac{1}{2012^{38}}\)

\(B=\frac{1}{2012}+\frac{37^{2012}}{2012^{39}}+\frac{2}{2012^{39}}\)

Ta có:

\(A-B=\frac{37^{2012}}{2012^{38}}-\frac{37^{2012}}{2012^{39}}+\frac{1}{2012^{38}}-\frac{2}{2012^{39}}\)

\(A-B=\frac{37^{2012}}{2012^{38}}\left(1-\frac{1}{2012}\right)+\frac{1}{2012^{38}}\left(1-\frac{2}{2012}\right)\)

\(A-B=\frac{37^{2012}}{2012^{38}}\left(\frac{2011}{2012}\right)+\frac{1}{2012^{38}}\left(\frac{2010}{2012}\right)\)

A - B > 0

=> A > B

A=2012³⁷/2012³⁸+ 37²⁰¹²/2012³⁸+1/2012³⁸

   = 1/2012+ 37²⁰¹²/2012³⁸+ 1/2012³⁸

Tương tự ta có: 

B=1/2012+ 37²⁰¹²/2012³⁹+1/2012³⁹+1/2012³⁹

Ta thấy: 1/2012=1/2012( ở 2 vế)

37²⁰¹²/2012³⁸ > 37²⁰¹²/ 2012³⁹( do cùng tử, mẫu nào nhỏ hơn thì phân số đó lớn hơn)

tương tự: 1/2012³⁸> 1/2012³⁹( 2012³⁸< 2012³⁹)

2012³⁹ là một số rất lớn nên 1/2012³⁹ rất bé và gần đến 0.

Vậy A>B.

37. D

38. A

37, D

38. D

Tiền vốn của sách đó là :

45000 x 20% = 9000(đồng)

Đ/s: 9000 đồng