giúp mìn với plssssssss
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1 She said that she was coming
2 She said that she wouldn't see me the following day
3 She said that he worked in a bank
4 She said that he was living in Paris for a few months
5 Lan said that she would be very busy the next day
6 Thu said that all the students would have a meeting the following sunday
7 Tam said that she could swim acroos that river
8 His sister said that she didn't buy that book
9 The boy said that they had to try their best to win the match
10 Her father said to her that she could go to the movies with her friends
11 Her classmate said that Lan was the most intellligent girl in their class
12 The teacher said that the sun rised in the east
Lông tơ chỉ có 1 chùm lông, sợi lông mảnh 1 lớp xốp giữ nhiệt và làm thân chim nhẹ.??
giữ nhiệt cho cơ thể, làm cho lông không thắm nước,làm đầu chim nhẹ
1-2+3-4+..........+99-100
=(1-2)+(3-4)+...+(99-100)
=(-1)+(-1)+...+(-1)
=(-1)*50
=-50
Đặt \(A=1-2+3-4+...+99-100\)
\(\Rightarrow A=\left(1-2\right)+\left(3-4\right)+...+\left(99-100\right)\) ( 50 cặp số )
\(\Rightarrow A=\left(-1\right)+\left(-1\right)+...+\left(-1\right)\) ( 50 số -1 )
\(\Rightarrow A=\left(-1\right).50\)
\(\Rightarrow A=-50\)
Vậy \(A=-50\)
13B 14D 15B 16A 17C 18C 19A 20D 21B 22C 23D 24C 25C 26A 27C 28A 29 30B 31C 32A
Câu 1:
1) ĐKXĐ: \(-2x+5\ge0\Leftrightarrow x\le\dfrac{5}{2}\)
2) ĐKXĐ: \(-x+1>0\Leftrightarrow x< 1\)
Câu 2:
1) \(=6\sqrt{2}+3\sqrt{2}-10\sqrt{2}+3\sqrt{3}=3\sqrt{3}-\sqrt{2}\)
2) \(=5-3+\sqrt{2}-1=1+\sqrt{2}\)
3) \(=15-3+5\sqrt{15}=12+5\sqrt{15}\)
4) \(=\dfrac{\sqrt{3}}{2}+\dfrac{\sqrt[]{3}}{3}+\dfrac{\sqrt{3}}{6}=\dfrac{3\sqrt{3}+2\sqrt{3}+\sqrt{3}}{6}=\dfrac{6\sqrt{3}}{6}=\sqrt{3}\)
ơ cái này dễ mà áp dụng lý thuyết là làm được