[4/(x^2-y^2)+(x+y)/(xy^2-x^2y)] / (x^2+xy-2y^2)/(x^2y+2xy^2) 其中,a=13,b=12

问题描述:

[4/(x^2-y^2)+(x+y)/(xy^2-x^2y)] / (x^2+xy-2y^2)/(x^2y+2xy^2) 其中,a=13,b=12

=[-(X-Y)/XY(X=Y)]*[XY/(X-Y)]=-1/(X+Y)=-1/25