化简：(x-1/2y-1)(x-1/2y+1)-(x-1/2y-1)^2
问题描述：
化简：(x-1/2y-1)(x-1/2y+1)-(x-1/2y-1)^2
^2 不是乘2,是指2的次方
答
1/2y应该是y/2吧?
(x-y/2-1)(x-y/2+1)-(x-y/2-1)^2
=[(x-y/2)-1][(x-y/2)+1]-[(x-y/2)-1]^2
=(x-y/2)^2-1-(x-y/2)^2+2(x-y/2)-1
=2(x-y/2)-2
=2x-y-2