问题描述: (x-2y)²-2(x+2y)(x-2y)+(x+2y)²,其中x=1,y=2 1个回答 分类:综合 2014-10-03 问题解答: 我来补答 (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 展开全文阅读