因为X^2+2*x+1=（x+1）^2≥0
∣x-y-2∣≥0
故要满足X^2+2*x+1+∣x-y-2∣=0
必须X^2+2*x+1=0；x-y-2=0
解得x=-1,y=3
故Y^x=3^(-1)=1/3.