2x²/(x+1)-3(x+1)/x²=-5令a=x²/(x+1)2a-3/a=-52a²+5a-3=0(2a-1)(a+3)=0a=1/2,a=-3x²/(x+1)=1/22x²-x-1=0(2x+1)(x-1)=0x=-1/2,x=1x²/(x+1)=-3x²+3x+3=0无解所以x=-1/2,x=1...