化简 x²-1分之x+3÷﹣x²+2x-1分之(x+3)(x-1)

(x+3)/( x²-1)÷[(x+3)(x-1)/(﹣x²+2x-1)]=(x+3)/( x²-1)÷[-(x+3)(x-1)/(x²-2x+1)]=(x+3)/( x²-1)÷[-(x+3)(x-1)/(x-1)²]=(x+3)/( x²-1)÷[-(x+3)/(x-1)]=-(x+3)/( x²-1)*(x-1)/(x+3)=-(x+3)/[( x-1)(x+1)]*(x-1)/(x+3)=-1/(x+1)