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26 tháng 9 2017

 Đặt A=3(22+1)(24+1)...(264+1) +1 

<=> A= (2+1)(22+1)(24+1)...(264+1) +1 

<=>(2-1)A=(2-1)(2+1)(22+1)(24+1)...(264+1) +1 

<=>1A=(22-1)(22+1)(24+1)...(264+1) +1 

<=>A =(24 -1)(24+1)...(264+1) +1 

........

<=> A=(264-1)(264+1) +1 

<=> A= 2128-1+1 = 2128

Vậy A=  2128

15 tháng 6 2019

1.A

2.D

3.C

4.B

5.D

15 tháng 6 2019

Nếu đề là rút gọn thì làm như này nha:

A = 3(2²+1)(2^4 + 1)....(2^64 + 1) + 1 

= (2²-1)(2²+1)(2^4 + 1)....(2^64 + 1) + 1 

= (2^4 - 1)(2^4 + 1)....(2^64 + 1) + 1 

= (2^8 - 1).(2^8 + 1)(2^16 + 1)(2^32 + 1)(2^64 + 1) + 1 

= (2^16 - 1)(2^16 + 1)(2^32 + 1)(2^64 + 1) + 1 

= (2^32 - 1)(2^32 + 1)(2^64 + 1) + 1 

= (2^64 - 1)(2^64 + 1) + 1 = 2^128 - 1 + 1 = 2^128. 

28 tháng 5 2017

Câu 1:

\(3x\left(12x+4\right)+9x\left(4x+3\right)\)

\(\Leftrightarrow3x\left(12x+4\right)+3x\left[3.\left(4x+3\right)\right]\)

\(\Leftrightarrow3x\left(12x+4\right)+3x\left(12x+6\right)\)

\(\Leftrightarrow3x\left[12x+4+12x+6\right]\)

\(\Leftrightarrow3x.\left(24x+10\right)\)

\(\Leftrightarrow72x^2+30x\)

Câu 2:

\(x\left(5+2x\right)+2x^2\left(x-1\right)\)

\(\Leftrightarrow5x+2x^2+2x^3-2x^2\)

\(\Leftrightarrow2x^3+5x\)

28 tháng 5 2017

Đề 1

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  • Wolfram|Alpha answers specific questions rather than explaining general topics
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Examples by Topic Quick video overview

Input:

 
1>3 x (12 x + 4) + 9 x (4 x + 3)

Open code

 
 
 

Inequality plot:

 
 
| | 1  | 3 x (24 x + 13)

Open code

 
EnlargeDataCustomizeA PlaintextInteractive
 

Alternate forms:

1>3 x (24 x + 13)

Open code

 
 
3 x (24 x + 13)<1

Open code

 
 
768/67 (x + 13/48)^2<1
 
 
 

Expanded form:

1>72 x^2 + 39 x

Open code

 
 
 

Solution:

  • Approximate form
1/48 (-13 - sqrt(201))<x<1/48 (sqrt(201) - 13)

Open code

 
 
 

Integer solution:

x = 0

Open code

 
 
 
22 tháng 10 2018

\(2x^3-x^2+5x+3\)

\(=2x^3+x^2-2x^2-x+6x^2+3\)

\(=x^2\left(2x+1\right)-x\left(2x+1\right)+3\left(2x+1\right)\)

\(=\left(2x+1\right)\left(x^2-x+3\right)\)

25 tháng 6 2016

1) \(\left(5x-4\right)^2-49x^2\)

\(=\left(5x-4\right)^2-\left(7x\right)^2\)

\(=\left(5x-4+7x\right)\left(5x-4-7x\right)\)( hằng đẳng thức số 3)

\(=\left(-2x-4\right)\left(12x-4\right)\)

2)\(\left(3x+1\right)^2-4\left(x-2\right)^2\)

\(=\left(3x+1\right)^2-\left(2\left(x-2\right)\right)^2\)

\(=\left(3x+1\right)^2-\left(2x-2\right)^2\)

\(=\left(3x+1-2x+4\right)\left(3x+1+2x-4\right)\)

\(=\left(x+5\right)\left(5x-3\right)\)

3) \(9\left(2x+3\right)^2-4\left(x+1\right)^2\)

\(=\left(3\left(2x+3\right)\right)^2-\left(2\left(x+1\right)\right)^2\)

\(=\left(6x+9\right)^2-\left(2x+2\right)^2\)

\(=\left(6x+9-2x-2\right)\left(6x+9+2x+2\right)\)

\(=\left(4x+7\right)\left(8x+11\right)\)

10 tháng 6 2016

A=4(3^2+1)(3^4+1)(3^8+1)...(3^64+1)

2A=8(3^2+1)(3^4+1)(3^8+1)...(3^64+1)

2A=(3^2-1)(3^2+1)(3^4+1)(3^8+1)...(3^64+1)

2A=(3^4-1)(3^4+1)(3^8+1)...(3^64+1)

2A=(3^8-1)(3^8+1)....(3^64+1)

2A=(3^16-1)...(3^64+1)

......

2A=(3^64-1)(3^64+1)

2A=3^128-1

A=(3^128-1)/2

=> A>B

10 tháng 6 2016

\(A=4\left(3^2+1\right)\left(3^4+1\right)...\left(3^{64}+1\right)\)

\(\Leftrightarrow4A=\left(3^2-1\right)\left(3^2+1\right)...\left(3^{64}+1\right)\)

\(\Leftrightarrow4A=\left(3^4-1\right)\left(3^4+1\right)...\left(3^{64}+1\right)\)

\(\Leftrightarrow4A=\left(3^8-1\right)\left(3^8+1\right)...\left(3^{64}+1\right)\)

\(\Leftrightarrow4A=\left(3^{16}-1\right)\left(3^{16}+1\right)...\left(3^{64}+1\right)\)

\(\Leftrightarrow4A=\left(3^{32}-1\right)\left(3^{32}+1\right)\left(3^{64}+1\right)\)

\(\Leftrightarrow4A=\left(3^{64}-1\right)\left(3^{64}+1\right)\Leftrightarrow4A=3^{128}-1\Leftrightarrow A=\frac{3^{128}-1}{4}\)

Ta có \(\frac{3^{128}-1}{4}< 3^{128}-1\Rightarrow A< B\)

Lâm Huyền:Bạn sai đề rồi B phải là 3128-1 chứ !

b) Ta có: \(\left(2+1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\left(2^{32}+1\right)-2^{64}\)

\(=\left(2+1\right)\left(2-1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\left(2^{32}+1\right)-2^{64}\)

\(=\left(2^2-1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\left(2^{32}+1\right)-2^{64}\)

\(=\left(2^4-1\right)\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\left(2^{32}+1\right)-2^{64}\)

\(=\left(2^8-1\right)\left(2^8+1\right)\left(2^{16}+1\right)\left(2^{32}+1\right)-2^{64}\)

\(=\left(2^{16}-1\right)\left(2^{16}+1\right)\left(2^{32}+1\right)-2^{64}\)

\(=\left(2^{32}-1\right)\left(2^{32}+1\right)-2^{64}\)

\(=2^{64}-1-2^{64}=-1\)