（x+1）/x² -2x²/(x+1)=1 两边乘x²(x+1)(x+ 1)²-2x^4=x²(x+1)x²+2x+1-2x^4=x^3+x²2x^4+x^3-2x-1=0x^3(2x+1)-(2x+1)=0(x^3-1)(2x+1)=0x1=1 x2=-1/2由于x≠-1所以x=-1/2