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

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.

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 )

tổng vận tốc của 2 ô tô:

\(210 : 2 = 150 ( k m / g i ờ )\)

vận tốc của ô tô đi từ \(A->B\)

\(150 : ( 2 + 3 ) x 2=42 ( k m / g i ơ ̀ )\)

vận tốc của ô tô đi từ \(B :\)

\(105 − 42 = 63 ( k m / g i ơ ̀ ) \)

đáp số : \(vA:42 k m / g i ơ ̀ \)

\(vB:63 k m / g i ơ ̀\)

\(∘White\)

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 ...

Bài 12

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}

bài 4:

C={6,7,8,9}

Bài 5:

14∉B, 9∈A, 9∈B, 0∈A

Bài 6: M={13,14,15,16}

13∈M, 19∉M, 12∉M, 16∈M