解x/(x+2)-(x²+2x+1)/(x+2)÷(x²-1)/(x-1)=x/(x+2)-(x+1)²/(x+2)÷(x-1)(x+1)/(x-1)=x/(x+2)-(x+1)²/(x+2)÷(x+1)=x/(x+2)-(x+1)/(x+2)=(x-x-1)/(x+2)=-1/(x+2)