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Bài nào :>

lỗi r

Bài 2:

\(\sqrt{2x-1}=5\)

=> 2x - 1 = 25

=> 2x = 26

=> x = 13

b) \(\sqrt[3]{3x+2}=-3\)

=> 3x + 2 = -27

=> 3x = -29

=> x = -29/3

P/s: Mỗi lần chỉ đc hỏi 1 bài thôi em nehs!

1. ĐK: 

a, \(x\ge\dfrac{5}{2}\)

b, \(\left\{{}\begin{matrix}x\ge0\\x\ne\dfrac{9}{4}\end{matrix}\right.\)

2.

a,ĐK: \(x\ge\dfrac{1}{2}\)

PT\(\Leftrightarrow2x-1=25\Rightarrow x=13\left(tm\right)\)

b,ĐK: \(\forall x\in R\)

PT\(\Leftrightarrow3x+2=-27=>x=-\dfrac{29}{3}\) (tm)

3.

a,\(\sqrt{5}.\sqrt{1,2}.\sqrt{24}=\sqrt{120}.\sqrt{1,2}=12\)

b,\(\dfrac{\sqrt{4444}}{\sqrt{1111}}=\dfrac{\sqrt{4}.\sqrt{1111}}{\sqrt{1111}}=2\)

c,\(\sqrt{\dfrac{3}{5}}+\sqrt{\dfrac{5}{3}}-\dfrac{1}{2}\sqrt{60}=\dfrac{8}{\sqrt{15}}-\sqrt{15}=-\dfrac{7}{\sqrt{15}}\)

d,\(\sqrt{5+2\sqrt{6}}+\sqrt{5-2\sqrt{6}}=\sqrt{3}+\sqrt{2}+\sqrt{3}-\sqrt{2}=2\sqrt{3}\)

Bài 5: 

a) Ta có: \(P=\dfrac{x+2}{x\sqrt{x}-1}+\dfrac{\sqrt{x}+1}{x+\sqrt{x}+1}-\dfrac{1}{\sqrt{x}-1}\)

\(=\dfrac{x+2}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}+\dfrac{x-1}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}-\dfrac{x+\sqrt{x}+1}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}\)

\(=\dfrac{x+2+x-1-x-\sqrt{x}-1}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}\)

\(=\dfrac{x-\sqrt{x}}{\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}\)

\(=\dfrac{\sqrt{x}}{x+\sqrt{x}+1}\)

b) Thay \(x=33-8\sqrt{2}\) vào P, ta được:

\(P=\dfrac{4\sqrt{2}-1}{33-8\sqrt{2}+4\sqrt{2}-1+1}\)

\(=\dfrac{\left(4\sqrt{2}-1\right)\left(33+4\sqrt{2}\right)}{1057}=\dfrac{132\sqrt{2}+32-33-4\sqrt{2}}{1057}\)

\(=\dfrac{128\sqrt{2}-1}{1057}\)

EX3

1. Which

2. How many

3. What

4. Whose

5. Where

6. How often 

7. Who 

8. How far

9. What

10. When

EX4

1. Who is a member of the Thai?

2. How many festivals in a year the Khmer have?

3. Which is the smallest ethnic group in Vietnam?

4. What is the biggest festival of Khmer people?     

5. Where we can find terraced fields?

6. How far from Ho Chi Minh city to Bom Bo village?

7. Why they built their houses on stilts?

8. What is the population of the Tay ethnic group?

9. How long the Tay have live in Vietnam?

10. Where the M'nong mainly live?

EX5:

1. Which ethnic group is the second largest population in Vietnam?

2. Sap dance is a typical dance of Muong people in the north.

3. Most ethnic minorities in Vietnam live in mountainous areas.

4. Thai ethnic minority is well known for beautifully woven garments.

5. The New Year celebration in Lao ethnic group is in lunar April.

6. Thai people account for approximately 1.8 % of Vietnam's population.

7. The Tay live on fertile plains where they cultivate rice and keep cattle and poultry.

8. How long have the Ede lived in the high plateau region in central Vietnam?

1. illegal

2. traffic jam

3. seatbelt

4. safely

5. railway station

6. safety

7. traffic signs

8. helicopter

9. tricycle

10. boat

Em ơi lần sau đăng tách ra nha!

lx

đâu vậy bạn

Bài 2: 

#include <bits/stdc++.h>

using namespace std;

long long a,b;

int main()

{

cin>>a>>b;

cout<<(a+b)*2<<endl;

cout<<a*b;

return 0;

}