(1)4-x²≥0 x≠1 -2≤x≤2 x≠1(2)x²+x+1=x²+x+1/4+3/4=(x+1/2)²+3/4>0x²-2x+1=(x-1)²≠0∴x≠1(3)x²-1≥0 1-x²≥0x-1≠0 x≠1x²≥1 x²≤1x²=1∴x=-1(4)|x|-x>0|x|>xx<0
1.-2<=X<=2 且X不等于12.X不等于13.X=-14.X<0
(1)-2<=x<=2且x不=1(2)x不=1(3)x=-1(4)x<0