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. They used to go to school by bike when they were young

38. Quang suggested that they sould visit the Royal Citadel first

39. The car was too expensive for my dad to buy

40. My teacher told me to follow his instruction if I wanted to pass that module

38 Quang suggested that the Royal Citadel should be visited first 

39 The car was too expensice for my dad to buy

40 My teacher told me to follow his instructions if I wanted to pass this module

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