câu 37
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Câu 9: Tính bằng cách thuận tiện nhất:
a) 876 × 64 – 876 × 54 |
=>876x(64-54)=876x10=8760
b) 37 × 25 + 37 × 35 + 37 × 39 + 37
37x(25+35+39)=37x99=3663
Chúc em học tốt
Câu 36: A
Câu 37: D
Câu 38: C
Câu 39: C
Câu 40: B
Câu 41: D
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
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:
\(\frac{4}{3.7}+\frac{4}{7.11}+\frac{4}{11.15}+\frac{4}{15.19}+\frac{4}{19.23}+\frac{4}{23.27}\)
\(\Rightarrow\frac{1}{3}-\frac{1}{7}+\frac{1}{7}-\frac{1}{11}+\frac{1}{11}-\frac{1}{15}+\frac{1}{15}-\frac{1}{19}+\frac{1}{19}-\frac{1}{23}+\frac{1}{23}-\frac{1}{27}\)
\(\Rightarrow\frac{1}{3}-\frac{1}{27}\)
\(=\frac{8}{27}\)
1) \(25+37-48-25-37=\left(25-25\right)+\left(37-37\right)-48=-48\)
2) \(37+35+36+37-14-15-16-17\)
\(=\left(37-17\right)+\left(35-15\right)+\left(36-16\right)+\left(37-14\right)\)
\(=20+20+20+23=83\)
Nếu bài toán có liên quan đến ruồi giấm, bạn chỉ cần nhớ rằng chỉ có hoán vị ở ruồi cái P thôi
Dễ nhận ra :
\(\dfrac{ab}{ab}=0,16\)
= ab (mẹ) x ab (bố)
Do bố không có hoán vị, nên để cho được ab thì kiểu gen của bố phải là \(\dfrac{AB}{ab}\)
Khi đó giao tử ab (bố)= 0,5
Suy ra giao tử ab (mẹ)= 0,16/ 0,5 = 0,32
Vậy ab (mẹ) là giao tử liên kết
Nên \(AB=ab=0,32\\ Ab=aB=0,18\)
Đáp án B nhé !