来自黄大贵的问题
分式化简(x^2+yz)/(x^2+(y-x)x-yz)+(y^2-zx)/(y^2+(z+x)y+zx)+(z^2=xy)/(z^2-(x-y)z-xy)再从输一遍好了，{(x^2+yz)÷[x^2+(y-z)x-yz]}+{(y^2-zx)÷[y^2+(z+x)y-zx]}+{(z^2+xy)÷[z^2-(x-y)z-xy]}，
分式化简(x^2+yz)/(x^2+(y-x)x-yz)+(y^2-zx)/(y^2+(z+x)y+zx)+(z^2=xy)/(z^2-(x-y)z-xy)
再从输一遍好了，{(x^2+yz)÷[x^2+(y-z)x-yz]}+{(y^2-zx)÷[y^2+(z+x)y-zx]}+{(z^2+xy)÷[z^2-(x-y)z-xy]}，
