11. Look at the text in ex. 10 again, then, in pairs, ask and answer questions about Charlie Foster, as in the examples.
1.Charlie / work / at a bank?     

SA: Does Charlie work at a bank?

SB: No, he doesn’t. He works a t a bakery.
2.Charlie / pack / a suitcase / at the moment? 

SA: Is Charlie packing a suitcase at the moment?

SB: Yes, he is.
3.Charlie I start work / at 4 o’clock every morning?

A: Does Charlie start work at 4 o'clock every morning?

B: Yes, he does.
4.Charlie / go on holiday / next week?

A: Is Charlie going to go on holiday next week?

B: No, he isn't . This week.
5.Charlie / sing to himself?

A: Does Charlie sing to himself?

B: Yes, he does.
6.Charlie / look for his tickets / right now?

A: Is Charlie looking for his tickets right now?

B: Yes, he is.
7.the plane / leave / in an hour?

A: Does the plane leave in an hour?

B: No, it doesn't. In an half an hour.
8.Charlie / go / Tahiti?

A: Does Charlie go to Tahiti?

B: Yes, he does.

1) \(\dfrac{8^{10}}{4^8}=\dfrac{\left(2^3\right)^{10}}{\left(2^2\right)^8}=\dfrac{2^{30}}{2^{16}}=2^{30-16}=3^{14}\)

2) \(\dfrac{4^2\cdot4^3}{2^{10}}=\dfrac{4^{2+3}}{\left(2^2\right)^5}=\dfrac{4^5}{4^5}=1\)

3) \(\dfrac{8^2\cdot4^5}{2^{20}}=\dfrac{\left(2^3\right)^2\cdot\left(2^2\right)^5}{2^{20}}=\dfrac{2^6\cdot2^{10}}{2^{20}}=\dfrac{2^{16}}{2^{20}}=\dfrac{1}{2^4}=\dfrac{1}{16}\)

4) \(\dfrac{2^7\cdot9^3}{6^5\cdot8^2}=\dfrac{2^7\cdot\left(3^2\right)^3}{2^5\cdot3^5\cdot\left(2^3\right)^2}=\dfrac{2^7\cdot3^6}{2^5\cdot3^5\cdot2^6}=\dfrac{2^7\cdot3}{2^{11}}=\dfrac{3}{2^4}=\dfrac{3}{16}\) 

5) \(\dfrac{2^{15}\cdot9^4}{6^6\cdot8^3}=\dfrac{2^{15}\cdot\left(3^2\right)^4}{3^6\cdot2^6\cdot\left(2^3\right)^3}=\dfrac{2^{15}\cdot3^8}{3^6\cdot2^6\cdot2^9}=\dfrac{2^{15}\cdot3^2}{2^{15}}=3^2=9\)

6) \(\dfrac{2^7\cdot9^3}{6^3\cdot8^2}=\dfrac{2^7\cdot\left(3^2\right)^3}{2^3\cdot3^3\cdot\left(2^3\right)^2}=\dfrac{2^7\cdot3^6}{2^3\cdot3^3\cdot2^6}=\dfrac{2^7\cdot3^3}{2^9}=\dfrac{3^3}{2^2}=\dfrac{27}{4}\)

đồng hồ chạy 45. 34 trên giờ

và khi đồng hồ ngừng nó sẽ dừng lại .

\(1,\left(1\right)\cdot x=1\)

\(\Rightarrow x=\dfrac{1}{1,\left(1\right)}\)

\(\Rightarrow x=1:\dfrac{10}{9}\)

\(\Rightarrow x=\dfrac{9}{10}=0,9\)

Vậy số thập phân x  thỏa mãn là 0,9 

\(1,\left(1\right).x=1\)

\(\left(1+\dfrac{1}{9}\right).x=1\)

\(\dfrac{10}{9}.x=1\)

\(x=1:\dfrac{10}{9}\)

\(x=\dfrac{9}{10}\)

\(x=0,9\)

Yêu cầu đề bài là gì, bạn cần ghi rõ ra nhé.

\(-\dfrac{1}{1\times4}-\dfrac{1}{4\times7}-\dfrac{1}{7\times10}-\dfrac{1}{10\times13}\)

\(=-\left(\dfrac{1}{1\times4}+\dfrac{1}{4\times7}+\dfrac{1}{7\times10}+\dfrac{1}{10\times13}\right)\)

\(=-\dfrac{1}{3}\cdot\left(\dfrac{3}{1\times4}+\dfrac{3}{4\times7}+\dfrac{3}{7\times10}+\dfrac{3}{10\times13}\right)\)

\(=-\dfrac{1}{3}\left(1-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{10}+\dfrac{1}{10}-\dfrac{1}{13}\right)\)

\(=-\dfrac{1}{3}\cdot\left(1-\dfrac{1}{13}\right)\)

\(=\dfrac{-1}{3}\cdot\dfrac{12}{13}\)

\(=\dfrac{-4}{13}\)

Ta có:

2024 ≡ 2024 (mod 2025)

2024² ≡ 1 (mod 2025)

2024³ ≡ 2024.2024² (mod 2025) ≡ 2024.1 (mod 2025) ≡ 2024 (mod 2025)

2024⁴ ≡ (2024²)² (mod 2025) ≡ 1² (mod 2025) ≡ 1 (mod 2025)

⇒ 2024 + 2024² + 2024³ + 2024⁴ ≡ 2024 + 1 + 2024 + 1 (mod 2025) 4050 ≡ (mod 2025) ≡ 0 (mod 2025)

Vậy (2024 + 2024² + 2024³ + 2024⁴) ⋮ 2025

\(\Rightarrow2025\cdot2024\cdot\left(1+2024^2\right)\) ⋮ 2025 

\(\Rightarrow\left(2024+2024^2+2024^3+2024^4\right)⋮2025\)

3x=4y=5z

=>\(\dfrac{3x}{60}=\dfrac{4y}{60}=\dfrac{5z}{60}\)

=>\(\dfrac{x}{20}=\dfrac{y}{15}=\dfrac{z}{12}\)

mà x-y-z=-21

nên Áp dụng tính chất của dãy tỉ số bằng nhau, ta được:

\(\dfrac{x}{20}=\dfrac{y}{15}=\dfrac{z}{12}=\dfrac{x-y-z}{20-15-12}=\dfrac{-21}{-7}=3\)

=>\(x=3\cdot20=60;y=15\cdot3=45;z=12\cdot3=36\)

\(4-\dfrac{2+\dfrac{1}{2}}{2-\dfrac{1}{2}}=4-\dfrac{\dfrac{4}{2}+\dfrac{1}{2}}{\dfrac{4}{2}-\dfrac{1}{2}}\\ =4-\dfrac{\dfrac{5}{2}}{\dfrac{3}{2}}=4-\dfrac{5}{3}\\ =\dfrac{12}{3}-\dfrac{5}{3}=\dfrac{7}{3}\)