x=-20,10(đoán vậy thui)

k mik nha

Học tốt

^_^

+> 51^n có chữ số tân cùng là 1 với mọi n thuộc N

+> 47^102=47^2.(47^4)^25=(...9).(...1)=(...9)

=>A=51^n+47^102=(...1)+(...9)=(...0)

Vì A có chữ số tận cùng là 0 

=> A chia hết cho 10

I was born and grown up on the poor land in Duc Tho district, Ha Tinh province. That’s where deeply attaches to me 24 years of life. If anyone who asks me that “What’s the thing your most proud of?” .I will answer that’s my hometown. Duc Tho is the land poor where the people live by rice cultivation, breeding, and fishing. Although the life is very difficult, but the people is very friendly, and studious. In Duc Tho, there is a Tung Anh village where called “Doctor village”. Duc Tho is also the home of Tran Phu Secretary General, and marked many memories of the great leader Ho Chi Minh.

If you come to Duc Tho, you will feel many interesting things, visiting Tran Phu tombstone, La Giang dyke, rowing on La driver, and enjoying the traditional songs. In the evening, they can enjoy a special food which is “mussel rice” – just only eat one time, you will never forget.

Beautiful and unobtrusive! Duc Tho always tries to grow, and to improve the life of people, but keeping the traditional culture.

Hk tốt

My home village is now different from the village in my father's story. in his story, my village is very poor. 

Everyone live a hard life that time. People lack of food, of money. Now, it is different. People don't live a hard life anymore. They have enough food, enough money, everyone got a house, and many more things. The only things that doesn't change is sentiment. Everyone always be very happy. They live together, help each other when they need, that is a luxury.

That makes my village a wonderful place for everyone. People are just farmer, but they solidarity in the face of penury. And when they have money in their hands, they still solidarity they are friendly with others, they are helpful, they are good people. That's about people. 
Landscape is still the old days. That river, that mountain. Nature is harmony with people. People live with nature, people product things of nature, and nature always open-handed with people, give them resource for them to build their house. That is what people seek, and they live with it very well. 

That's all I can say about my home village, in my opinion, my village is a wonderful place. War does not determine who is right, only who is left:" Ask not what your country can do for you but what you can do for your country"

k mk đi rồi mk đưa link cho 

27\(\le\)3ⁿ\(\le\)243

3³\(\le\)3ⁿ\(\le\)3⁵

\(\Rightarrow\)n = 3; 4; 5

Hk tốt

27 < 3ⁿ < 243

<=> 3³ < 3ⁿ < 3⁵

<=> 3 < n < 5

=> n = 3 ; 4 ; 5

(1) cân bằng 

(2) đứng yên

(3) chiều

(4) phương

(5) chiều

6²⁰ . 6⁴ⁿ = 6²⁰⁰

6^{20 + 4n} = 6²⁰⁰

\(\Rightarrow\)20 + 4n = 200

                 4n = 200 - 20

                 4n = 180

                   n = 180 : 4

                   n = 45

Hk tốt

\(6^{20}.6^{4n}=6^{200}\)

\(\Rightarrow6^{4n}=6^{200}:6^{20}\)

\(\Rightarrow6^{4n}=6^{180}\)

\(\Rightarrow6^{4n}=6^{4.45}\)

\(\Rightarrow n=45\)

12x - 33 = 3² . 3³

12x - 33 = 3⁵

12x        = 3⁵ + 33

12x        = 276

    x        = 276 : 12

    x        = 23

Hk tốt

\(12x-33=3^2\cdot3^3\)

\(12x-33=3^5\)

\(12x-33=243\)

\(12x=243+33\)

\(12x=276\)

\(x=276:12\)

\(x=23\)