Câu 2:

9/1974: Ghi - nê Bít -xao

6/1975: Mozambique

11/1975: Angola

Câu 1:

17/8/1945: Indonesia

2/9/1945: Việt Nam

12/10/1945: Lào

1946 - 1950: Ấn Độ

1952: Liên minh phòng thủ châu Âu

1954 - 1962: Algérie

1960: 17 nước châu Phi (sgk có)

1/1/1959: Cuba

Câu 2:

9/1974: Ghi - nê Bít -xao

6/1975: Mozambique

11/1975: Angola

Câu 1:

17/8/1945: Indonesia

2/9/1945: Việt Nam

12/10/1945: Lào

1946 - 1950: Ấn Độ

1952: Liên minh phòng thủ châu Âu

1954 - 1962: Algérie

1960: 17 nước châu Phi (sgk có)

1/1/1959: Cuba

Bài 3 : 

a) $Zn + 2HCl \to ZnCl_2 + H_2$
b) $n_{H_2} = n_{Zn} = \dfrac{6,5}{65} = 0,1(mol)$

$V_{H_2} = 0,1.22,4 = 2,24(lít)$

c) $n_{ZnCl_2} = n_{Zn} = 0,1(mol)$

$m_{ZnCl_2} = 136.0,1 = 13,6(gam)$

Bài 4 : 

a) $2Zn + O_2 \xrightarrow{t^o} 2ZnO$

b)

$n_{Zn} = \dfrac{6,5}{65} = 0,1(mol)$
$n_{O_2} = \dfrac{1}{2}n_{Zn} = 0,05(mol)$

$V_{O_2} = 0,05.22,4 = 1,12(lít)$

c) $n_{ZnO} = n_{Zn} = 0,1(mol) \Rightarrow m_{ZnO} = 0,1.81 = 8,1(gam)$

\(=\left(\left(x+2\right)\left(x+5\right)\right)\left(\left(x+3\right)\left(x+4\right)\right)-24\)

\(=\left(x^2+7x+10\right)\left(x^2+7x+12\right)-24\)

Đặt \(x^2+7x+10=y\)ta có:

    \(y\left(y+2\right)-24\)

\(=y^2+2y-24\)

\(=y^2-4y+6y-24\)

\(=y\left(y-4\right)+6\left(y-4\right)\)

\(=\left(y-4\right)\left(y+6\right)\)

\(=\left(x^2+7x+10-4\right)\left(x^2+7x+10+6\right)\)

\(=\left(x^2+7x+6\right)\left(x^2+7x+16\right)\)

\(=\left(x^2+x+6x+6\right)\left(x^2+7x+16\right)\)

\(=\left(x\left(x+1\right)+6\left(x+1\right)\right)\left(x^2+7x+16\right)\)

\(=\left(x+1\right)\left(x+6\right)\left(x^2+7x+16\right)\)

Trời..Hình như bạn gửi cả cái đề kt luôn ấy

Nhìn qua mà không muốn làm:v

Bài 11:

a: UCLN(28;54;96)=2

b: BCNN(12;90;150)=1800

\(30+2x=4^{2017}:4^{2015}\)

\(\Rightarrow30+2x=4^2=16\)

\(\Rightarrow2x=16-30=-14\)

\(\Rightarrow x=-14:2=-7\)

30 + 2x = 4²⁰¹⁷ : 4²⁰¹⁵

30 + 2x = 4²

30 + 2x = 16

        2x = 16 - 30

        2x = -14

          x = - 7

30+2.x =\(4^{2017}:4^{2015}\)

\(\Rightarrow30+2x=4^{2017-2015}\)\(\Rightarrow30+2x=16\)

\(\Rightarrow2x=-14\Rightarrow x=-7\)

Vậy x=

20. eat

21. is playing

22. washes

23. rings

24. bring

eat

is playing

washes

rings

bring

Chúc em học tốt

20 eat

21 is playing

22 washes

23 rings

24 bring