x²-x-3=0则x²-x=3
原式=[(x+1)/x(x-1)-x/(x-1)²]÷(x-x+1)/(x-1)
=(x²-1-x²)/x(x-1)²÷1/(x-1)
=-1/x(x-1)²*(x-1)
=-1/(x²-x)
=-1/3