những bài tự luận bạn đăng tầm 10 câu mỗi lần đăng thôi nhé, chứ dài quá ngại làm lắm

1 T

2 F

3 F

4 They wear masks

5 Yes, they do

6 Because it made the writer excited and helped him remember about his childish

IV

1 I am having a wonderful time in Ha Long Bay

sửa

1 T

2 F

3 F

4 children wear maskes , parade

5 yes they do

6 because it made him/her excited nad helped him remember about his/her childish 

1. T
2. F
3. F
4. They wear masks.
5. Yes. they are. 
6. Because it made him excited and helped him remember about his childlish.

\(Cl_2+Mg-^{t^o}\rightarrow MgCl_2\\ MgCl_2+2NaOH\rightarrow Mg\left(OH\right)_2+2NaCl\\ Mg\left(OH\right)_2-^{t^o}\rightarrow MgO+H_2O\\ MgO+H_2SO_4\rightarrow MgSO_4+H_2O\)

Bài 6

a) (3x² + 5) + [(2x² - 5x) - (5x² + 4)]

= 3x² + 5 + (2x² - 5x - 5x² - 4)

= 3x² + 5 + 2x² - 5x - 5x² - 4

= (3x² + 2x² - 5x²) - 5x + (5 - 4)

= -5x + 1

---------‐----------

b) (x + 2)(x² - 2x + 4)

= x.x² - x.2x + x.4 + 2.x² - 2.2x + 2.4

= x³ - 2x² + 4x + 2x² - 4x + 8

= x³ + (-2x² + 2x²) + (4x - 4x) + 8

= x³ + 8

-------------------

c) (4x³ - 8x² + 13x - 5) : (2x - 1)

= (4x³ - 2x² - 6x² + 3x + 10x - 5) : (2x - 1)

= [(4x³ - 2x²) - (6x² - 3x) + (10x - 5)] : (2x - 1)

= [2x²(2x - 1) - 3x(2x - 1) + 5(2x - 1)] : (2x - 1)

= (2x - 1)(2x² - 3x + 5) : (2x - 1)

= 2x² - 3x + 5

Bài 8:

\(B=\frac{a}{ab+a+abc}+\frac{b}{bc+b+1}+\frac{2c}{ac+2c+abc}\\ =\frac{1}{b+1+bc}+\frac{b}{bc+b+1}+\frac{2}{a+2+ab}\\ =\frac{1}{b+1+bc}+\frac{b}{bc+b+1}+\frac{abc}{a+abc+ab}\\ =\frac{1}{b+1+bc}+\frac{b}{bc+b+1}+\frac{bc}{1+bc+b}\\ =\frac{1+b+bc}{b+1+bc}=1\)

Bài 9:

\(A=\frac{a}{ab+a+1}+\frac{ba}{abc+ab+a}+\frac{c.ab}{ac.ab+c.ab+ab}\\ =\frac{a}{ab+a+1}+\frac{ab}{1+ab+a}+\frac{1}{a+1+ab}\\ =\frac{ab+a+1}{ab+a+1}=1\)

Bài 10:

\((x-1)^{20}\geq 0, \forall x; (y+2)^{20}\geq 0, \forall y\)

Do đó để tổng $(x-1)^{20}+(y+2)^{20}=0$ thì $(x-1)^{20}=(y+2)^{20}=0$

$\Rightarrow x=1; y=-2$

Khi đó:

$A=2.1^5-5.(-2)^3+4=46$

1 Never has he been late for work

2 The man who is talking to the lady over there is my new boss

3 The postman asked the boy if Mr Pike lived there

4 A new school will be built next month

5 It is not easy to find an apartment in a big city

bài đọc thì bạn chụp thêm phần kia nữa nha

1. are

2. prevent

3. ways

4. energy

5. one

6. drivers

7. in

8. people