1.|x-1|=0 (y-2)^2=0
X=1 Y=2 -x^2+(-y^2)+x^y=-1-4+1=-4
2.m为偶数,n为奇数,mn为偶数,(-1)^m=1 (-1)^n=-1 (-1)^mn=1
（-1）＾m+（-1）＾n+（-1）＾mn
=1-1+1
=1
3.有多种情况`````