1. |2x-2|+|y+3|+|2z-4|=0,
则2x-2=0,x=1,
y+3=0,y=-3,
2z-4=0,z=2,
则(x+y)^z=(1-3)^2=4
2.已知a0,ab>0,|b|>|c|>|a|.
(1)根据条件用“”填空：
①a < c,②b < 0,③c > b,④b < a,⑤|b|-b > |b|+b,⑥a+b+c < 0
(2)化简：|a|+|b|+|a+c|-|c|+|b+c|-|a+b|=-a-b+a+c-c-b-c+a+b=a+b+c.
3.1/n(n+1)=1/n-1/(n+1)
1/(1×2)+1/(2×3)+···+1/n(n+1)=1-1/(n+1)