x-3/x^-1÷x^2-2x-3/x^2+2x+1+1/x-1,其中x=-2
网友回答
(x-3)/(x^2-1)÷(x^2-2x-3)/(x^2+2x+1)+1/(x-1)
=(x-3)/(x^2-1)*(x^2+2x+1)/(x^2-2x-3)+1/(x-1)
=(x-3)/(x-1)(x+1)*(x+1)^2/(x-3)(x+1)+1/(x-1)
=(x-3)/(x-1)*(x+1)/(x-3)(x+1)+1/(x-1)
=1/(x-1)+1/(x-1)
=2/(x-1)
=2/(-2-1)
=-2/3