解:y=-4/x带入法得:x^2-2x-4/x=-2x^3-2x^2+2x-4=0解得x有且仅有唯一的解x=2故y=-2答题不容易,望采纳 过程:x^2(x-2)+2(x-2)=0(x-2)(x^2+2)=0x^2+2≥0,故x仅有唯一解x=2