解：原式=1/(x+1)-(3-x²+1)/(x-1)*(x-1)²/x(x+2)(x-2)=1/(x+1)+(x+2)(x-2)/(x-1)*(x-1)²/x(x+2)(x-2)=1/(x+1)+(x-1)/x=(x+x²-1)/x(x+1)=(x²+x-1)/(x²+x)当x²+x= 时
