拜托加上括号好不好?(y³-y²-y+1)/(y²-1) × (x²-1)/(x³-x²-x+1) × (x-1)/(y-1)=[y(y²-1)-(y²-1)]/(y²-1)× (x²-1)/[x(x²-1)-(x²-1)]× (x-1)/(y-1)=(...