问题
解答题
化简:(x-y-z)-(x+y-z)-(x+y-z).
答案
(x-y-z)-(x+y-z)-(x+y-z)
=x-y-z-x-y+z-x-y+z
=(1-1-1)x+(-1-1-1)y+(-1+1+1)z
=-x-3y+z.
化简:(x-y-z)-(x+y-z)-(x+y-z).
(x-y-z)-(x+y-z)-(x+y-z)
=x-y-z-x-y+z-x-y+z
=(1-1-1)x+(-1-1-1)y+(-1+1+1)z
=-x-3y+z.