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17 tháng 12 2022

a: \(A=\dfrac{\sqrt{x}-\sqrt{x}+1}{\sqrt{x}\left(\sqrt{x}-1\right)}:\dfrac{x-1-x+4}{\left(\sqrt{x}-2\right)\left(\sqrt{x}-1\right)}\)

\(=\dfrac{1}{\sqrt{x}\left(\sqrt{x}-1\right)}\cdot\dfrac{\left(\sqrt{x}-2\right)\left(\sqrt{x}-1\right)}{3}\)

\(=\dfrac{\sqrt{x}-2}{3\sqrt{x}}\)

b: Để A<0 thì căn x-2<0

=>0<x<4

17 tháng 12 2022

a: \(A=\dfrac{\sqrt{x}-\sqrt{x}+1}{\sqrt{x}\left(\sqrt{x}-1\right)}:\dfrac{x-1-x+4}{\left(\sqrt{x}-2\right)\left(\sqrt{x}-1\right)}\)

\(=\dfrac{1}{\sqrt{x}\left(\sqrt{x}-1\right)}\cdot\dfrac{\left(\sqrt{x}-2\right)\left(\sqrt{x}-1\right)}{3}\)

\(=\dfrac{\sqrt{x}-2}{3\sqrt{x}}\)

b: Để A<0 thì căn x-2<0

=>0<x<4

16 tháng 12 2021

BẢO THẦY N guyễn Hàng Minh ý 

16 tháng 12 2021

Nguyễn Hàng Minh :D ?

14 tháng 8 2021

2. He asked her where she was going.

3. He asked which way they had gone.

4. I told her to bring it back if it didn't fit.

5. She told us not to try to open it then.

6. I asked her if it was going to be a fine day that day.

7. She said that he was not at home.

8. The girl wanted to know if the bus station was far away.

9. Tom told Ann not to stay out late.

10. He asked her to let him borrow her car.

11. Thomas asked Jean if he had seen his gloves.

12. I told Mary not to leave the window open.

13. She said that she would have a cup of tea with me.

14. She said that she would pay him if she could.

15. She asked what I was going to do the next summer.

7 tháng 2 2016

thì vừa là đường trung tuyến vừa là đường trung trực thì tam giác đó cân chứ sao trời!

7 tháng 2 2016

vẽ hình sẽ ra ngay thôi

22 tháng 9 2021

\(ĐK:x\in R\\ PT\Leftrightarrow\sqrt{\left(x+\dfrac{1}{2}\right)^2}=7-2x\\ \Leftrightarrow\left|x+\dfrac{1}{2}\right|=7-2x\\ \Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=7-2x,\forall x+\dfrac{1}{2}\ge0\\x+\dfrac{1}{2}=2x-7,\forall x+\dfrac{1}{2}< 0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{13}{6},\forall x\ge-\dfrac{1}{2}\left(tm\right)\\x=\dfrac{15}{2},\forall x< -\dfrac{1}{2}\left(ktm\right)\end{matrix}\right.\Leftrightarrow x=\dfrac{13}{6}\)

22 tháng 9 2021

Mình cảm mơn nhìuu nha

16 tháng 8 2021

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

3 tháng 8 2021

\(n_{Fe_3O_4}=\dfrac{8}{232}=\dfrac{1}{29}\left(mol\right)\)

\(Fe_3O_4+8HCl\rightarrow FeCl_2+2FeCl_3+4H_2O\)

\(\dfrac{1}{29}.......\dfrac{8}{29}................\dfrac{2}{29}\)

\(m_{HCl}=\dfrac{8}{29}\cdot36.5=10.06\left(g\right)\)

\(m_{FeCl_3}=\dfrac{2}{29}\cdot162.5=11.21\left(g\right)\)

25 tháng 2 2021

ờ...tớ ko nhầm thì thừa are

nếu bỏ are thì she's making a papper boat

26 tháng 2 2021

Bỏ are, she's making a paper boat

16 tháng 10 2021

A B' A' B

N I S R

\(i=i'\)

\(\Rightarrow i'=30^o\)