化简求值 (y³-y)/[(xy+1)²-(x+y)²] × (x+1)/(x+y)y,其中x=11,y=-12

(y³-y)/[(xy+1)²-(x+y)²] × (x+1)/(x+y)y=[y（y+1)（y-1) ]/[（xy+1+x+y）（xy+1-x-y）] ×（x+1)/（x+y)y=[y（y+1)（y-1) ]/[（x+1)(y+1)（x-1)(y-1)] × （x+1)/（x+y）y=y/（x+1)(x-1) ×（x+1)/...请问倒数第二步是什么意思？带入了么？是的