x+(1/x-1)+(x^2-3x+4/1-x^2)

问题描述:

x+(1/x-1)+(x^2-3x+4/1-x^2)

原式=x+(x+1-x²+3x-4)/(x+1)(x-1)
=x-(x²-4x+3)/(x+1)(x-1)
=x-(x-1)(x-3)/(x+1)(x-1)
=(x²+x-x+3)/(x+1)
=(x²+3)/(x+1)