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DD
14 tháng 9 2021

\(A=\sqrt{2+\sqrt{3}}+\sqrt{2-\sqrt{3}}\)

\(A\sqrt{2}=\sqrt{4+2\sqrt{3}}+\sqrt{4-2\sqrt{3}}\)

\(=\sqrt{3+2\sqrt{3}+1}+\sqrt{3-2\sqrt{3}+1}\)

\(=\sqrt{\left(\sqrt{3}+1\right)^2}+\sqrt{\left(\sqrt{3}-1\right)^2}\)

\(=\left|\sqrt{3}+1\right|+\left|\sqrt{3}-1\right|\)

\(=\sqrt{3}+1+\sqrt{3}-1=2\sqrt{3}\)

Suy ra \(A=\frac{2\sqrt{3}}{\sqrt{2}}=\sqrt{6}\)

Ta có đpcm. 

1 tháng 12 2021

Em chụp rộng ra , đề bài thiếu

1 tháng 12 2021

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24 tháng 5 2021

III. 

A. 

1. B

2. C

3. B

4. A

5. D

B. 

1. C

2. B

3. B

4. A

5. C

18 tháng 11 2021

1 b c b a d

2 c b b a c nha

24 tháng 5 2021

1 The meeting was canceled 3 days ago

2 She told me she was watching a film with her sister then

3 I admire the guitarist who is perfroming on the stage

4 Had it not been for Pauline's interest, the project would have been abandoned 

24 tháng 5 2021

IV. 

1. The meeting was canceled 3 days ago.

2. She told me shewas watching a film with her sister then

3. I admire the guitarist who is performing on the stage

4. Had it not been for Pauline's interest, the project was abandoned. (chắc thế)

28 tháng 3 2021

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28 tháng 3 2021

Chụp rõ đề hơn đi bạn.

26 tháng 9 2021

a) \(\dfrac{A}{x-2}=\dfrac{x^2+3x+2}{x^2-4}\)

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

\(\Leftrightarrow\dfrac{A}{x-2}=\dfrac{x+1}{x-2}\Leftrightarrow A=x+1\)

b) \(\dfrac{M}{x-1}=\dfrac{x^2+3x+2}{x+1}\)

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

\(\Leftrightarrow\dfrac{M}{x-1}=x+2\Leftrightarrow M=\left(x-1\right)\left(x+2\right)=x^2+x-2\)

4 tháng 8 2021

asked how much that computer was

wanted to know if I had the keys

asked Sam why he hadn't come to the party

asked Jane where she was going for her holidays

asked me if I spoke English

asked how old her mother was

asked me whether I was British or American

4 tháng 8 2021

1 Tom asked how much that computer was

2 The officer wanted to know if I had wanted the key

3 Ann asked Sam why he hadn't come to her party

4 He asked Jane where she was going for her holiday

5 He asked me if I spoke E

6 He asked how old her mother was 

7 He asked me whether I was British or American

2 tháng 1 2022

a) x(x + 4) - 3x - 12 = 0

x(x + 4) - 3(x + 4) = 0

(x + 4)(x - 3) = 0

x = -4 hoặc x = 3

b) 2x(x - 4) - x + 4 = 0

2x(x - 4) - (x - 4) = 0

(x - 4)(2x - 1) = 0

x = 4 hoặc x = 1/2

c) 5x(x - 3) - x + 3 = 0

5x(x - 3) - (x - 3) = 0

(x - 3)(5x - 1) = 0

x = 3 hoặc x = 1/5.

2 tháng 1 2022

a) x(x + 4) - 3x - 12 = 0

x(x + 4) - 3(x + 4) = 0

(x + 4)(x - 3) = 0

x = -4 hoặc x = 3

b) 2x(x - 4) - x + 4 = 0

2x(x - 4) - (x - 4) = 0

(x - 4)(2x - 1) = 0

x = 4 hoặc x = 1/2

c) 5x(x - 3) - x + 3 = 0

5x(x - 3) - (x - 3) = 0

(x - 3)(5x - 1) = 0

x = 3 hoặc x = 1/5.