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3 tháng 7 2016

a. Đề:\(3\left(2x-1\right)^2+7\left(3y+5\right)^2=0\)

Giải :\(\Rightarrow\hept{\begin{cases}2x-1=0\\3y+5=0\end{cases}}\Rightarrow\hept{\begin{cases}2x=0+1=1\\3y=0-5=-5\end{cases}\Rightarrow\hept{\begin{cases}x=\frac{1}{2}\\y=-\frac{5}{3}\end{cases}}}\)

b. Đề : \(x^2+y^2-2x+10y+26=0\)

Giải : \(\Leftrightarrow x^2-2.1.x+1+y^2+2.5.y+25=0\)

\(\Leftrightarrow\left(x-1\right)^2+\left(y+5\right)^2=0\)

\(\Leftrightarrow\hept{\begin{cases}x-1=0\\y+5=0\end{cases}\Leftrightarrow\hept{\begin{cases}x=0+1=1\\y=0-5=-5\end{cases}}}\)

Đây là bài 1 bài 2 đang ghi nha 

t i c k nha cảm ơn

12 tháng 8 2016

\(A=\left(2+1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\)

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

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

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

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

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

\(B=2^{32}\)

=> \(A< B\)

12 tháng 8 2016

ta có A= \(\left(2+1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\)

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

=\(2^{32}-1\)    (ấp dụng các hằng đẳng thức )

=> A=232-1

B=232

=> A<B

Ta có: \(A=\left(2+1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\)

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

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

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

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

\(=2^{32}-1< 2^{32}\)

\(\Leftrightarrow A< B\)

16 tháng 9 2019

\(A=\left(2+1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\)

\(A=\left(2-1\right)\left(2+1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\)

\(A=\left(2^2-1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\)

\(A=\left(2^4-1\right)\left(2^4+1\right)\left(2^8+1\right)\)

\(A=\left(2^8-1\right)\left(2^8+1\right)\)

\(A=2^{16}-1< 2^{16}\)

16 tháng 9 2019

Mình làm theo cách tính nhé !

\(A=\left(2+1\right).\left(2^2+1\right).\left(2^4+1\right).\left(2^8+1\right)\)

\(A=3.\left(4+1\right).\left(16+1\right).\left(256+1\right)\)

\(A=3.5.17.257\)

\(\Rightarrow A=65535\) 

\(B=2^{16}=65536\) 

Từ đó \(\Rightarrow A< B\)

12 tháng 7 2015

 

A = 3(2^2+1)(2^4+1)(2^8+1)(2^16+1)+1 

 =(22-1)(22+1)(24+1)(28+1)(216+1)+1

=(24-1)(24+1)(28+1)(216+1)+1

=(28-1)(28+1)(216+1)+1

=(216-1)(216+1)+1

=232-1+1

=232 = B

vậy A=B

19 tháng 7 2015

A = (2 - 1)(2 + 1)(2^2 + 1 )(2^4 + 1 ) (2^8 + 1)(2^16 + 1)  ( nhân vói 2 - 1 = 1 Gía không thay dổi)

A = ( 2 ^2 - 1 )(2^2 + 1 )(2^4  + 1 )(2^8 + 1 )(2^16 + 1 )

A = ( 2^4 - 1 )(2^4 + 1)(2^8 + 1)(2^16 + 1)

A = (2^8 - 1)(2^8 + 1)(2^16 + 1)

A = (2^16 - 1)(2^16 + 1 )

A = 2^32 - 1 <2^32 = B 

VẬy A < B

A=(2+1)x(22+1)x(24+1)x(28+1)x(216+1)

= 3.5.17.257.65537

   = 42949672995 = 232 ⇒A = B mình nhé 
6 tháng 7 2018

1/

\(A=\left(2+1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^{16}+1\right)=\left(2-1\right)\left(2+1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^{16}+1\right)\)

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

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

Vì 232 > 223 => 232-1>223-1 hay A>B

2/

\(A=x^2+y^2=\left(x-y\right)^2+2xy=5^2+2.14=25+28=53\)

\(B=\left(x+y\right)^2=\left(x-y\right)^2+4xy=5^2+4.14=25+56=81\)