A = 2032128

a) \(2\left(x-y\right)\left(x+y\right)+\left(x+y\right)^2+\left(x-y\right)^2\)

\(=2\left(x-y\right)\left(x+y\right)+\left(x+y+x-y\right)^2-2\left(x+y\right)\left(x-y\right)\)

\(=\left(2x\right)^2=4x^2\)

b) \(\left(x-y+z\right)^2+\left(z-y\right)^2+2\left(x-y+z\right)\left(y-z\right)\)

\(=\left(x-y+z\right)^2+\left(y-z\right)^2+2\left(x-y+z\right)\left(y-z\right)\)

\(=\left(x-y+z+y-z\right)^2-2\left(x-y+z\right)\left(y-z\right)+2\left(x-y+z\right)\left(y-z\right)\)

\(=x^2\)

A=(3+1)(3^2+1)(3^4+1)(3^8+1)(3^16+1)

=>2A=(3-1)(3+1)(3²+1)(3⁴+1)(3⁸+1)(3¹⁶+1)

=(3²-1)(3²+1)(3⁴+1)(3⁸+1)(3¹⁶+1)

=(3⁴-1)(3⁴+1)(3⁸+1)(3¹⁶+1)

=(3⁸-1)(3⁸+1)(3¹⁶+1)

=(3¹⁶-1)(3¹⁶+1)

=3³²-1

=>A=\(\frac{3^{32}-1}{2}\)

 Đến đậy thì bạn có thể so sánh r, mik ko làm dc là vì B=3³²+-1 mik ko hỉu í bạn là dấu +hay -

A=(3+1)(3^2+1)(3^4+1)(3^8+1)(3^16+1) => 2A=(3-1)(3+1)(3^2+1)(3^4+1)(3^8+1)(3^16+1) => 2A=3^32 - 1 => A= (3^32 - 1) / 2

B = 3^32 - 1

=> A < B

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

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

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

2/ 

1/       (3x+1)^2=3xx+6x+1

          4(x-2)^2=4(xx-4x+4)=4xx-16x+16

Ta có 

3xx+6x+1-4xx+16x-16=-xx+22x-15

2/        x^8+x^7+1

<=> 4(x^2 + 2x + 1) + 4x^2 - 4x +1 - 8(x^2 - 1) = 11 
<=> 4x^2 + 8x + 4 + 4x^2 - 4x +1 - 8x^2 +8 - 11 = 0 
<=> 4x + 2 = 0 
<=> x = - 1/2

\(4\left(x+1\right)^2+\left(2x-1\right)^2-8\left(x-1\right)\left(x+1\right)=11\)

\(4\left(x^2+2x+1\right)+4x^2-4x+1-8\left(x^2-1\right)=11\)

\(4x^2+8x+4+4x^2-4x+1-8x^2+8=11\)

\(4x+13=11\)

\(4x=-2\)

\(x=-\frac{1}{2}\)

(a + b + c)² = a² + b² + c² + 2ab + 2bc + 2ac. 
(1/a + 1/b + 1/c)² = 1/a² + 1/b² + 1/c² + 2(1/ab + 1/bc + 1/ac) = 4 
<=> 1/a² + 1/b² + 1/c² + 2(bcac + abac + abbc)/(a²b²c²) = 4 
<=> 1/a² + 1/b² + 1/c² + 2abc(a + b + c)/(a²b²c²) = 4 
<=> 1/a² + 1/b² + 1/c² + 2 = 4 
(vi` abc(a + b + c) = a² b² c²) 
<=> 1/a² + 1/b² + 1/c² = 2 !!

\(x^2y-xy^2+x^3-y^3\)

\(=x^2\left(y-x\right)-y^2\left(y-x\right)\)

\(=\left(x^2-y^2\right)\left(y-x\right)\)

\(=\left(x-y\right)\left(x+y\right)\left(y-x\right)\)

25 + 62 + 85 + 32 + 25 = 229

ai k mik

mik k lại, xin thề

số đó là

254

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