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

a) Ta có: \(A=\dfrac{x^2+x}{x^2-2x+1}:\left(\dfrac{x+1}{x}-\dfrac{1}{1-x}+\dfrac{2-x^2}{x^2-x}\right)\)

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

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

\(=\dfrac{x^2}{x-1}\)

b) Ta có: |2x-5|=3

\(\Leftrightarrow\left[{}\begin{matrix}2x-5=-3\\2x-5=3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=2\\2x=8\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\left(loại\right)\\x=4\left(nhận\right)\end{matrix}\right.\)

Thay x=4 vào A, ta được:

\(A=\dfrac{4^2}{4-1}=\dfrac{16}{3}\)

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

hình bé quá

sin 65⁰=cos 35⁰
\(cos70^0=sin30^0\)
\(tan80^0=cot20^0\)
\(cot68^0=tan32^0\)

Ko nhìn chữ bn ơi, bn cho to hình một tý

(135-35).(-37)+37.(-42-58)

= 135-35.0.(-42)-58

=100.0.100

=0

(vì số nào nhân với 0 vẫn bằng 0)

CHÚC BẠN HỌC GIỎI.NĂM MỚI VUI VẺ , HẠNH PHÚC

TK MÌNH NHÉ

(135 - 35) . (-37) + 37 . (-42 - 58)

= 100 . (37 - 37) . (-100)

= 100 . 0 . (-100)

= 0 - (-100)

= 0

số 0 chia hay nhân với số nào cũng bằng 0 nha

( 135 - 35 ) . (-37) + 37 . (-42 - 58 )

= 100 . 0 - (-100)

= 0

( vì số nào nhân 0 vẫn chính bằng 0 )

k mk nha

Mk cảm ơn bạn nhiều 

a: =>(x-1)(x-2)=0

=>x=1 hoặc x=2

b: TH1: x>=0

=>2x=3x+2

=>x=-2(loại)

TH2: x<0

=>-2x=3x+2

=>-5x=2

=>x=-2/5(nhận)

c: TH1: x>=0

=>2x=3x+4

=>-x=4

=>x=-4(loại)

TH2: x<0

=>-2x=3x+4

=>-5x=4

=>x=-4/5(nhận)

14 Lan asked Thu where she could find the new cartoons

15 Phong asked Lan if their teacher asked them to clean up the room

16 She asked me to give her some money

17 Tam asked Thu if she would be there for five days

18 The students asked their teacher to give them easier homework

19 She asked her husban if they needed some help

20 Lan asked Hoa is she might have a look at her picture

21 Lam asked Lan if their class would take part in that competition

1 Lan said she would be busy the day after

2 Nam said he was told to be at school before 7 a.m

3 The teacher said all the homework had to be done carefully

4 She said she didn't buy that book

5 The boys said they had to try their best to win the match

6 Her classmate said Lan was the most intelligent girl in their class

7 Mary told her friend she would expect to see her the next Wednesday

8 The teacher asked me where my father worked

9 A tourist asked how far it was from HCM city to Vung Tau

10 Mrs Brown asked Thu what language she spoke

11 His friend asked him what time his schools began

12 Lan asked Len how much this dress cost

13 She asked me what kind of program I liked best