1: Ta có: \(\dfrac{1}{\sqrt{x}-1}+\dfrac{1}{\sqrt{x}+1}+1\)

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

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

1 knowing the answer, they told us

2 the unique handicraft, we didn't like it

3 We looked into these machines so that we could find out the method 

We looked into these machines so as to find out the method 

4 Jack's poverty, everyone looks up to him

5 In order to choose the best chair, Linda looked through this catalouge 

6 is not as dirty as this one

7 I didn't play as successfully as Linda

8 A dog can't run as fast as a horse

A dog runs more slowly than a horse

9 No rivers in the world is as long as the Nile

10 No one in my family talks as politely as Linda

1 was arrested before the garden by the boy yesterday

2 his cats taken care of carefully by Jack everyday

3 Has the country been protected from Covid-19 successfully

4 is reported that the man is running out of money

is reported to be running out of money\

5 has been said that the thief got out of the prison

has been said to have got out of the prison

6 was thought that Mary had turned down the job

Mary was thought to have  turned down the job

PTHH: 2Al + 6HCl → 2AlCl₃ + 3H₂

PTHH: Mg(OH)₂ + 2HCl → MgCl₂ + 2H₂O

PTHH: Fe₂O₃ + 6HCl → 2FeCl₃ + 3H₂O

PTHH: K₂O + 2HCl → 2KCl + H₂O

Lần sau em đăng câu hỏi đúng box để mọi người hỗ trợ nha

PTHH: 2Al + 6HCl → 2AlCl₃ + 3H₂

PTHH: Mg(OH)₂ + 2HCl → MgCl₂ + 2H₂O

PTHH: Fe₂O₃ + 6HCl → 2FeCl₃ + 3H₂O

PTHH: K₂O + 2HCl → 2KCl + H₂O

Bài nào?

5.

\(A=B\Leftrightarrow\left\{{}\begin{matrix}x-5\ge0\\x+2>0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\ge5\\x>-2\end{matrix}\right.\Leftrightarrow x\ge5\)

6.

a, ĐK: \(\left\{{}\begin{matrix}2-\sqrt{x-1}\ge0\\x-1\ge0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}\sqrt{x-1}\le2\\x\ge1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\le5\\x\ge1\end{matrix}\right.\Leftrightarrow1\le x\le5\)

b, ĐK: \(\left\{{}\begin{matrix}x-2\ge0\\x-2\ne0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\ge2\\x\ne2\end{matrix}\right.\Leftrightarrow x>2\)

c, ĐK: \(\left\{{}\begin{matrix}x^2-4\ge0\\x-2\ge0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\ne\pm2\\x>2\end{matrix}\right.\Leftrightarrow x>2\)

d, ĐK: \(\left\{{}\begin{matrix}6x-1\ge0\\x+3\ge0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\ge\dfrac{1}{6}\\x\ge-3\end{matrix}\right.\Leftrightarrow x\ge\dfrac{1}{6}\)

1 is grown in many countries in the world

2 was invented by Graham bell many years ago

3 has been used for many years

4 Is English practiced by Lan everyday

5 will be taken out of the city 

6 can this letter be sent by Mary 2 days ago

7 is being made from vegetables

8 must be finished before Sunday

9 hadn't been used for a long time

10 Will I be met at the airport by Jack tomorrow

12 It is thought that Maradona is.....

13 It has been believed that the job is.....

14 It was explained that this powerful.....

1B

2 bạn có chép đúng đề?

3D

4B

5A

6A

7A

8A

9B

10B

11C

12A

13C

14B

15A

16C