(x+2y)(x-2y)-(2y-x)(-2x-y)其中x=8,y=-8

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(x+2y)(x-2y)-(2y-x)(-2x-y)其中x=8,y=-8(x+2y)(x-2y)-(2y-x)(-2x-y)其中x=8,y=-8(x+2y)(x-2y)-(2y-x)(-2x-y)其中

(x+2y)(x-2y)-(2y-x)(-2x-y)其中x=8,y=-8
(x+2y)(x-2y)-(2y-x)(-2x-y)其中x=8,y=-8

(x+2y)(x-2y)-(2y-x)(-2x-y)其中x=8,y=-8
(x+2y)(x-2y)-(2y-x)(-2x-y)
=(x+2y)(x-2y)+(x-2y)(-2x-y)
=(x-2y)[(x+2y)+(-2x-y)]
=(x-2y)(-x+y)
代入x=8 y=-8
=-24*16
=-384

代入

(x+2y)(x-2y)-(2y-x)(-2x-y)
=(-8)*24-(-24)*(-8)
=-(8*24)-(8*24)
=-16*24
=-384

直接做撒 带入