(x+1)/x²-2x²/(x+1)=1令t=(x+1)/x²,那么x²/(x+1)=1/t所以原方程变为：t-2/t=1t²-t-2=0,(t+1)(t-2)=0,所以t=-1,或t=2当t=(x+1)/x²=-1时,x²+x+1=0,此时Δ=1-4