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1:

a: \(P=B:A\)

\(=\dfrac{3\sqrt{x}-3-2\sqrt{x}+4+\sqrt{x}+2}{x-4}:\dfrac{4\sqrt{x}-1}{x-4}\)

\(=\dfrac{2\sqrt{x}+3}{x-4}\cdot\dfrac{x-4}{4\sqrt{x}-1}=\dfrac{2\sqrt{x}+3}{4\sqrt{x}-1}\)

b: Để P nguyên thì \(2\sqrt{x}+3⋮4\sqrt{x}-1\)

=>\(4\sqrt{x}+6⋮4\sqrt{x}-1\)

=>\(4\sqrt{x}-1+7⋮4\sqrt{x}-1\)

=>4căn x-1 thuộc {1;-1;7;-7}

=>căn x thuộc {1/2;0;2}

mà x nguyên và x>=0 và x<>4

nên x thuộc {0}

7 tháng 12 2021

1 his illness, he cannot come

2 her busyness, she couldn't help us

3 his illness, he tries to go to school on time

4 the bad weather, we tried to finish the work on the road

5 the bad weather, we got to the station late

6 the old house, she liked it

7 not wearing any shoes, Carol ran outside to see what was happening

8 being afraid of flying, Fiona had to get on the plane

7 tháng 6 2021

9 Although the girl works hard from morning till night, her step mother isn't happy

10 Rice is grown in tropical countries

11 The countryside is more peaceful than the city, but I prefer living in the city

12 A lot of Chung Cakes are made on Tet holiday

13 Although Little Pea works hard from morning till night, her mother isn't happy

14 An ordinary car goes more slowly than a sport car

15 An's sister performs better than him

16 Many fesstivals are held by the Thai every year

17 I enjoy hanging out with my best friends

18 If you don't hurry up, you will be late for the race

25 tháng 10 2021

\(a,A=\dfrac{x+2\sqrt{x}+1+x-2\sqrt{x}+1-3\sqrt{x}-1}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}\\ A=\dfrac{2x-3\sqrt{x}+1}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}=\dfrac{\left(\sqrt{x}-1\right)\left(2\sqrt{x}-1\right)}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}=\dfrac{2\sqrt{x}-1}{\sqrt{x}+1}\\ b,A=\dfrac{2\left(\sqrt{x}+1\right)-3}{\sqrt{x}+1}=2-\dfrac{3}{\sqrt{x}+1}\in Z\\ \Leftrightarrow\sqrt{x}+1\inƯ\left(3\right)=\left\{1;3\right\}\left(\sqrt{x}+1\ge1\right)\\ \Leftrightarrow\sqrt{x}\in\left\{0;2\right\}\\ \Leftrightarrow x\in\left\{0;4\right\}\left(tm\right)\)

25 tháng 10 2021

a) \(A=\dfrac{\sqrt{x}+1}{\sqrt{x}-1}+\dfrac{\sqrt{x}-1}{\sqrt{x}+1}-\dfrac{3\sqrt{x}+1}{x-1}\)

\(\Rightarrow A=\dfrac{\left(\sqrt{x}+1\right)^2}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}+\dfrac{\left(\sqrt{x}-1\right)^2}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}-\dfrac{3\sqrt{x}+1}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}\)

\(\Rightarrow A=\dfrac{x+2\sqrt{x}+1}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}+\dfrac{x-2\sqrt{x}+1}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}-\dfrac{3\sqrt{x}+1}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}\)

\(\Rightarrow A=\dfrac{x+2\sqrt{x}+1+x-2\sqrt{x}+1-3\sqrt{x}-1}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}\)

\(\Rightarrow A=\dfrac{2x-3\sqrt{x}+1}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}\)

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

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

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

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

6 tháng 1 2022

kt giữa kì ??? nếu vậy thì em không giúp

12 tháng 11 2021

Em cần gấp ạ

22 tháng 11 2021

1B

2C

3D

4A

5B

6D

7A

8B

9A

10C

22 tháng 11 2021

Bạn giúp mình bài dưới luôn được không ạ 

11 tháng 11 2021

Ai giúp mình bài này với ạ

 

 

11 tháng 11 2021

C - D - A - E - B

Nick suggested going out for a walk.

Would you mind lending me your book?

 

 

Thân mến phản hồi đến em!