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72^45-72^44=72^44(72-1)=72^44*71
72^44-72^43=72^43(72-1)=72^43*71
=>72^45-72^44>72^44-72^43
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a: 199^20=1568239201^5
2003^15=8036054027^5
=>199^20<2003^15
b: 3^99=27^33>27^21=11^21
Lời giải:
a.
$199^{20}<200^{20}=(2.100)^{20}=2^{20}.10^{40}=(2^{10})^2.10^{40}< (10^4)^2.10^{40}=10^8.10^{40}=10^{48}$
$2003^{15}> 2000^{15}=(2.10^3)^{15}=2^{15}.10^{45}> 2^{10}.10^{45}> 10^3.10^{45}=10^{48}$
$\Rightarrow 199^{20}< 2003^{15}$
b.
$3^{99}=(3^9)^{11}=19683^{11}$
$11^{21}< 11^{22}=(11^2)^{11}=121^{11}$
Hiển nhiên $19683^{11}> 121^{11}$
$\Rightarrow 3^{99}> 121^{11}> 11^{21}$
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a) Ta có:
5²³ = 5.5²²
Do 6 > 5 nên 6.5²² > 5.5²²
Vậy 6.5²² > 5²³
b) Ta có:
2¹⁶ = 2³.2¹³ = 8.2¹³
Do 8 > 7 nên 8.2¹³ > 7.2¹³
Vậy 2¹⁶ > 7.2¹³
c) Ta có:
21¹⁵ = (3.7)¹⁵ = 3¹⁵.7¹⁵
27⁵.49⁸ = (3³)⁵.(7²)⁸ = 3¹⁵.7¹⁶
Do 16 > 15 nên 7¹⁶ > 7¹⁵
⇒ 3¹⁵.7¹⁶ > 3¹⁵.7¹⁵
Vậy 27⁵.49⁸ > 21¹⁵
a: 5^23=5*5^22<6*5^22
=>6*5^22 lớn hơn
b: 7<8
=>7*2^13<8*2^13=2^16
=>2^16 lớn hơn
c: 21^15=3^15*7^15
27^5*49^8=3^15*7^16
mà 15<16
nên 27^5*49^8 lớn hơn
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\(a.10^{30}=\left(10^3\right)^{10}=1000^{10}\\ 2^{100}=\left(2^{10}\right)^{10}=1024^{10}\)
Vì 100010 < 102410 => 1030 < 2100
\(b,333^{444}=\left(111\cdot3\right)^{444}=111^{444}\cdot3^{444}=111^{444}\cdot81^{111}\\ 444^{333}=\left(111\cdot4\right)^{333}=111^{333}\cdot4^{333}=111^{333}\cdot64^{111}\)
Vì 111444 >111333 ; 81111 > 64111 => 333444 > 444333
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Ex1: Complete the sentences with: a, an, some, any
1. We didn’t buy …………flowers.
2. This evening I’m going out with ………….friends of mine.
3. “Have you seen ………..good films recently?”
– “No, I haven’t been to the cinema for ages”.
4. I didn’t have ……………money, so I had to borrow………..
5. Can I have ………milk in my coffee, please?
6. I was too tired to do………work.
7. There is .................. banana in the basket.
8. I need ..................tea.
9. Are there ..................tomatoes in the fridge?
10. We have .........rice, but we don't have ......meat.
11. There's ..................orange on the table.
12. I'd ..................apple juice.
13. He has ............TV and ............computer.
14. Would you ..................ice- cream?
15. I have............... friends in Hue.
16. Do you have ...............dogs or cats at home?
17. Would you ..................cup of tea?
18. I would .................. cakes, please.
19. Can I have ............glass of milk?
20. Thank you. And .........box of chocolates would be fine.
21. I don't have ............... paper.
22. Is there ............... petrol in the car?
23. I buy ...............fruit, but I don't have ...............vegetables.
24. Do you have ............... stamps? I need two.
25. I need ...............butter to make a cake.
26. I don't have ...............free time today. Sorry.
27. Are there............... potatoes in the basket?
28. There is ...............ink-pot on the table.
EX2: Find and corect the mistakes
Câu 1: How much is a bowl of fried rice? - They is 2,500 dong.
A B C D
Câu 2: What is you favorite food?
A B C D
Câu 3: What weather are you ?
A B C D
Câu 4: Are there some books on the table.
A B C D
Câu 5: He is going to visits Ngoc Son temple.
A B C D
Câu 6: Are there some books on the table.
A B C D
EX3: Complete the sentences with: “much, many, few, a few, little, a little”
1. He isn’t very popular. He has ………..friends.
2. Ann is very busy these days. She has ………..free time.
3. Did you take …………….photographs when you were on holiday?
4. The museum was very crowded. There were too………..people.
5. Most of the town is modern. There are …………..old buildings.
6. We must be quick. We have………..time.
7. Listen carefully, I’m going to give you ……….advice.
8. Do you mind if I ask you……….questions?
9. This town is not a very interesting place to visit, so …….tourists come here.
10. I don’t think Jill would be a good teacher. She’s got …………..patience.
11. “Would you milk in your coffee?” – “yes, please. ………….”
12. This is a very boring place to live. There’s ………….to do.
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5300 = (52)150 = 25150
3453 > 3450 = (33)150 = 27150
Vì 25150 < 27120
=> 5300 < 3453
Ủng hộ mk nha ^_-
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b) \(3^{453}>3^{450}=\left(3^3\right)^{150}=27^{150}\)
\(5^{300}=\left(5^2\right)^{150}=25^{150}\)
\(27>25\Leftrightarrow27^{150}>25^{150}\)
nên \(3^{453}>5^{300}\).
a) \(2^{161}>2^{160}=\left(2^{16}\right)^{10}>13^{10}\)