(a-1)²+|b+2|=0,(a-1)²>=0,|b+2|>=0,(a-1)²=0,|b+2|=0,a=1,b=-2(a+b)/(a-b)=(1-2)/(1+2)=-1/3[若是a+b/a-b=1+(-2)/1-(-2)=1-2+2=1,]
解: 由已知有, a-1=0 b+2=0 解得 a=1 b=-2 故 (a+b)/(a-b)=(1+2)/(1-2)=3/(-1)=-3
a=1 b=-2 答案是-1/3