Câu 1:

PTHH: 2Al + 3H₂SO₄ → Al₂(SO₄)₃ + 3H₂

PTHH: Na₂O + H₂SO₄ → Na₂SO₄ + H₂O

PTHH: Cu(OH)₂ + H₂SO₄ → CuSO₄ + 2H₂O

Câu 2:

a, \(n_{H_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)

PTHH: Fe + H₂SO₄ → FeSO₄ + H₂

Mol:     0,2     0,2                            0,2

b, \(m_{Fe}=0,2.56=11,2\left(g\right)\)

c, \(C_{M_{ddH_2SO_4}}=\dfrac{0,2}{0,1}=2M\)

\(1,\\ a,=\dfrac{\left(3+2\sqrt{3}\right)\sqrt{3}}{3}+\dfrac{\left(2+\sqrt{2}\right)\left(\sqrt{2}-1\right)}{1}\\ =\dfrac{3\sqrt{3}+6}{3}+\sqrt{2}=\sqrt{3}+1+\sqrt{2}\\ b,=\left(\dfrac{\sqrt{5}+\sqrt{2}}{3}-\dfrac{\sqrt{5}-\sqrt{2}}{3}+1\right)\cdot\dfrac{1}{\left(\sqrt{2}+1\right)^2}\\ =\dfrac{\sqrt{5}+\sqrt{2}-\sqrt{5}+\sqrt{2}+3}{3}\cdot\dfrac{1}{\left(\sqrt{2}+1\right)^2}\\ =\dfrac{2\sqrt{2}+3}{3\left(3+2\sqrt{2}\right)}=\dfrac{1}{3}\)

\(2,\\ A=2x+\sqrt{\left(x-3\right)^2}=2x+\left|x-3\right|\\ =2\left(-5\right)+\left|-5-3\right|=-10+8=-2\\ B=\dfrac{\sqrt{\left(2x+1\right)^2}}{\left(x-4\right)\left(x+4\right)}\left(x-4\right)^2=\dfrac{\left|2x+1\right|\left(x-4\right)}{x+4}\\ B=\dfrac{17\cdot4}{12}=\dfrac{17}{3}\)

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 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

đăng r hạn chế đăng lại b nhé, sẽ có ng trl mà

a)

=15(can6-1)/(6-1)+4/(4-2)-12/(3-4)

=3(can6-1)+2+12

=3\(\sqrt{6}\)-3+2+12

=17+3can6

các câu còn lại tương tự liên hợp mẫu 

c: Ta có: \(\dfrac{3+2\sqrt{3}}{\sqrt{3}}+\dfrac{2+\sqrt{2}}{\sqrt{2}+1}-\left(2+\sqrt{3}\right)\)

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

\(=\sqrt{2}\)