`A = 2+ 2^2 + 2^3 + .... + 2^10`

`A = 2 + 2^2 + (2^3 + 2^4 + 2^5+2^6) +  (2^7 + 2^8 + 2^9 +2^10)`

`A =  2 + 2^2  + 2^2 .(2 + 2^2 + 2^3 +2^4) + 2^6 .(2 + 2^2 + 2^3 +2^4) `

`A =  6 + 2^2. 30 + 2^6 . 30`

`A = 6 + 30 . (2^2 + 2^6) `

Mà `30 . (2^2 + 2^6) ` chia hết 5; 6 không chia hết 5

=> A không chia hết 5

`4x - 128 = 2^3 . 3^2`

`=> 4x - 128 = 8 .9`

`=> 4x - 128 = 72`

`=> 4x = 72 + 128`

`=> 4x = 200`

`=> x = 200 : 4`

`=> x = 50`

Vậy ...

4x -128 = 2³ .3²

4x-128=8 . 9

4x-128=72

4x = 72 +128

4x =  200

x = 200 : 4

x = 50

Vậy x = 50

\(30⋮x,5< x< 30\)

\(\Rightarrow x\inƯ\left(30\right)=\left\{1;2;3;5;6;10;15;30\right\}\)

Mà \(5< x< 30\)

\(\Rightarrow x\in\left\{6;10;15\right\}\)

Vậy...

\(x< 30\) mà 30 < 30?

1 They don't have an air conditioner in their living room

2 It is Nam's cat

3 Why don't we tidy our bedroom?

1 They don't have an air conditioner in their living room

2 It is Nam's cat

3 Why don't we tidy our bedroom?

1 on

2 behind

4 near

5 to

6 in

7 in

8 to

1 on

2 behind

4 near

5 to

6 in

7 in

8 to

9 A

10 B

11 B

12 D

13 B

14 A

15 B

16 C

17 A

18 B

19 B

20 D

21 A

22 D

23 A

24 C

25 C

26 B

27A

28 C

29 D

30 C

1 My father works in a hospital in the city

2 Hoa gets up at six o'clock and brushes her teeth

3 Those are Miller's shoes

4 There are six rooms in Minh's house

5 I am not learning English at the moment

1/ Ta có : ( -16 ) + 23 + x = ( -16 )

 <=> 23 + x                        = ( -16 ) + 16 

<=> 23 + x                            = 0

<=> x                                      = 0 -23

<=> x                                    = -23

Vậy x = -23

2/ Ta có : 2.x - 35 = 15

<=> 2.x                    = 15 + 35

<=>    2.x                  = 50

<=> x                         = 50 : 2

<=> x                        = 25

Vậy x = 25

1/    -16 + 23 + x = -16 

[(-16) +23] +x = -16

7 + x = -16

x= -16 - 7 

x= -23

2/   2x - 35 = 15

2x= 15 + 35

2x = 50

x= 50:2

x= 25

Chúc bạn làm bài tốt

\(10+2x=4^5:4^3\)

\(10+2x=4^2=16\)

\(2x=16-10\)

\(2x=6\)

\(x=6:2\)

\(x=3\)

\(2x+10=4^5:4^3\\ 2x+10=4^2\\ 2x+10=16\\ 2x=6\\ x=3\)

Vậy x = 3