Giúp mk b8+b9 với ah
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1. I am not tall enough to reach the ceiling
2. She is sociable enough to make friends easily
3. He is looking at himself in the mirror at the moment
4. I have to stop smoking
5. Mr. Kerry used to run 5 miles every morning when he was a teenager
6. We really like her sense of humor
7. He ought not to play computer games
8. Hilary doesn't hace to wear uniform at school
1. I am not tall enough to reach the ceiling
2. She is sociable enough to make friends easily
3. He is looking at himself in the mirror at the moment
4. I have to stop smoking
5. Mr. Kerry used to run 5 miles every morning when he was a teenager
6. We really like her sense of humor
7. He ought not to play computer games
8. Hilary doesn't hace to wear uniform at school
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(A=1+\dfrac{1}{2}+\dfrac{1}{2^2}+...+\dfrac{1}{2^{2022}}\)
\(\Rightarrow2^{2022}.A=2^{2022}+\dfrac{2^{2022}}{2}+\dfrac{2^{2022}}{2^2}+...+\dfrac{2^{2022}}{2^{2022}}\)
\(\Rightarrow2^{2022}.A=2^{2022}+2^{2021}+2^{2020}+...+1\)
\(\Rightarrow2^{2022}.2.A=2^{2023}+2^{2022}+2^{2021}+...+2\)
\(\Rightarrow2^{2023}.A-2^{2022}.A=\left(2^{2023}+2^{2022}+2^{2021}+...+2\right)-\left(2^{2022}+2^{2021}+2^{2020}+...+1\right)\)
\(\Rightarrow2^{2022}.A\left(2-1\right)=2^{2023}-1\)
\(\Rightarrow A=\dfrac{2^{2023}-1}{2^{2022}}\).
-Câu b bạn làm tương tự.
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tổng vận tốc 2 xe là :
210 : 2 =105 ( km/giờ )
Tổng số phần bằng nhau là :
2+ 3 = 5 ( phần )
Vận tốc xe ô tô đi từ A là :
150 : 5 x 2 = 42 ( km/giờ )
Vận tốc xe ô tô đi từ B là :
105 - 42 = 63 ( km/giờ )
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Bài 2 :
a, - Để đồ thi hàm số song song với đường thẳng :\(\Leftrightarrow\left\{{}\begin{matrix}a=a^,\\b\ne b^,\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}m^2-4=5\\2m-7\ne-1\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}m^2=9\\2m\ne6\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}m=\pm3\\m\ne3\end{matrix}\right.\)
\(\Rightarrow m=-3\)
Vậy ...
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Bài 1: A=\(\left\{H,I,N,O,C\right\}\)
Bài 2: M=\(\left\{3,4,5,6\right\}\)
Bài 3: \(A=\left\{6,23\right\}\\ B=\left\{3,u,t\right\}\\ C=\left\{cua\right\}\)
D={cua,cá,ốc}
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