(x-2y)²-2(x+2y)(x-2y)+(x+2y)²,其中x=1,y=2

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(x-2y)²-2(x+2y)(x-2y)+(x+2y)²,其中x=1,y=2
(x-2y)²-2(x+2y)(x-2y)+(x+2y)²,其中x=1,y=2

(x-2y)²-2(x+2y)(x-2y)+(x+2y)²,其中x=1,y=2
(x-2y)²-2(x+2y)(x-2y)+(x+2y)²
= [ (x - 2y) - ( x + 2y)]²
= [ x - 2y - x - 2y]²
= ( -4y)² = 16y²
把x = 1 ,y = 2代入上式得：原式 = 16 × 2² = 64