A=\(\left|x^2+y^2+5+2x-4y\right|-\left|-\left(x+y-1\right)^2+2xy\right|\)

\(\Leftrightarrow A=x^2+y^2+5+2x-4y-\left|-\left(x^2+2xy-2x-2y+y^2+1\right)\right|+2xy\)

\(\Leftrightarrow A=x^2+y^2+5+2x-4y+x^2-2xy+2x+2y-y^2-1+2xy\)

\(\Leftrightarrow A=2x^2-4+4x-2y\)

thay \(x=2^{2011};y=16^{503}\) vào A ta được:

\(2.\left(2^{2011}\right)^2-4+4.\left(2^{2011}\right)-2.\left(16^{503}\right)\)

A không có giá trị

1: =(16x^2-8x+1)-y^2

=(4x-1)^2-y^2

=(4x-1-y)(4x-1+y)

2: =(x^2-2xy+y^2)-z^2

=(x-y)^2-z^2

=(x-y-z)(x-y+z)

3: =(x^2+4xy+4y^2)-16

=(x+2y)^2-4^2

=(x+2y-4)(x+2y+4)

4: =(x^2-4xy+4y^2)-16

=(x-2y)^2-4^2

=(x-2y-4)(x-2y+4)

a) (x+4)(x² - 4x + 16 ) - x(x-5) = 264

x³ + 4³ - x(x² - 25) = 264

x³ + 64 - x³ + 25x= 264

64 + 25x = 264

25x = 264-64

25x= 200

x = \(\dfrac{200}{25}\) = 8

b) (x-2)³ - (x-2)(x² + 2x + 4 ) + 6(x-2)(x+2) = 60

x³ - 6x² + 12x - 8 - ( x³ - 2³ ) + 6(x² - 4 ) = 60

x³ - 6x² + 12x - 8 - x³ + 8 + 6x² -24 = 60

12x - 24 = 60

12x = 60 + 24

12x = 84

x = \(\dfrac{84}{12}\) = 7

bài 1 câu b có sai đề không bạn?