`B.I.`

`1.` a

`2.` c

`3.` d

`4.` a

`5.` D

`6.` C

`7.` B

`8.` A

`II.`

`1.` Shrine 

`2.` impressed 

`3.` traditional 

`4.` for

`C.I.` 

`1.` T

`2.` T

`3.` F

`4.` F

`II.` 

`1.` Yes, Jeans the most popular kind of clothes almost everywhere, rich people and poor people wear them too. 

`2.` Jeans the only kind of tradtional clothes in the United States.

`3.` Because everybody wants to be modern, young and independent. 

`4.` (Tự trả lời)

`D.I.`

`1.` Many letters can be written to my pen pal in english by me.

`2.` has done

`3.` I wish today were a holiday.

`4.` I missed the bus, so I came to the meeting late. 

B

I

1 A

2 C

3 D

4 A

5 D

6 C

7 B

8 A

II

1 shrine

2 impressed

3 traditional

4 for 

C

1 T

2 T

3 F

4 F

II

1 Yes, they are

2 In the United States

3 Because they want to be modern, young and independent

4 Yes, I do. Because wearing jeans is very comfortable 

D

I

1 Many letters can be written to my penpal in England

2 has been doing

3 I wish today were a holiday

4 I missed the bus, so I came to the meeting late

II

1 Last sunday was a beautiful day

2 My class will have a picnic in the park

3 Suddenly. It rained very hard with strong wind

4 We got wet because none of us brought raincoats

Bài `1`

`a, (x+2)^2 =x^2 +4x+4`

`b, (x-5)^2=x^2 -10x+25`

`c,(2x-y)^2=(2x)^2- 2*2x*y+y^2=4x^2-4xy+y^2`

`d,(3x^2-2y)^2= (3x^2)^2 - 2*3x^2*2y +(2y)^2=9x^4-12x^2y +4y^2`

`e,,(2x-y)(4x^2+2xy+y^2)= (2x)^3-y^3=8x^3-y^3`

`f,(x+3)(x^2-3x+9)=x^3+3^3=x^3+27`

1.N hóa trị lll

   N hóa trị lV

2.Fe hóa trị lll

1, \(x^2\) - \(x\) + \(\dfrac{1}{4}\) = 0

   \(x^2\) - 2.\(x\).\(\dfrac{1}{2}\) + \(\dfrac{1}{4}\) = 0

   (\(x\) - \(\dfrac{1}{2}\))² = 0

    \(x\)  - \(\dfrac{1}{2}\) =0

     \(x\)        = \(\dfrac{1}{2}\)

2,    \(x^2\) - 10\(x\) = -25

     \(x^2\) - 10\(x\) + 25 = 0

      (\(x\) - 5)² = 0

       \(x\) - 5 =0

       \(x\)       = 5

Bạn đăng câu hỏi lên đi

e:

\(E=\left(\dfrac{\sqrt{15}-\sqrt{20}}{2-\sqrt{3}}+\dfrac{\sqrt{21}-\sqrt{7}}{1-\sqrt{3}}\right):\dfrac{1}{\sqrt{7}-\sqrt{5}}\)

\(=\left(-\dfrac{\sqrt{5}\left(2-\sqrt{3}\right)}{2-\sqrt{3}}-\dfrac{\sqrt{7}\left(1-\sqrt{3}\right)}{1-\sqrt{3}}\right)\cdot\dfrac{\sqrt{7}-\sqrt{5}}{1}\)

\(=-\left(\sqrt{7}+\sqrt{5}\right)\left(\sqrt{7}-\sqrt{5}\right)\)

=-2

f: \(F=\sqrt{3}+1+2-\sqrt{3}=3\)

a) phép tính đã cho bằng 24x²y³z² : (-6x²y²z²) +(-12x³y²z³) : (-6x²y²z²) + 36x²y²z² : (-6x²y²z²) = -4y+2xz-6. Thế x,y,z vào rồi tính nha

câu b khi nãy mình giải ở dưới rồi :)

Giải chỗ thế cho mình với mình chưa hiểu chõi thế làm như nào bạn giải giúp mình với. Sắp 2h30 rồi 

Mình rút gọn tới không thể rút được nữa thì thế để tính :) -4y+2xz-6=(-4)(-2.5)+2(-25).4-6 bạn tự bấm máy tính nhá