(x+y+z)(x+y+z)等于一定要对的

(x+y+z)(x+y+z)等于一定要对的 (x+y+z)(-x+y+z)(x-y+z)(x+y-z)等于什么? （x+y-z）*（x+y-z)-(x-y+z)*(x-y-z)等于多少 z,x,y,等于多少? （x-y+z）（x+y+z）等于多少. （x+y+z)(x+y-z)等于多少 （x+y-z）乘以（x-y-z）等于? （x-y-z）乘以（z-x+y）等于? （x-y+z）（x+y+z）等于多少? (x-y-z)(x-y-z)(x-y-z)等于多少? (x-y-z)(x-y=z)等于多少?错了，应该是(x-y-z)(x-y+z)不好意思 设函数z=z（x,y)由方程2sin(x+2y-3z)=x+2y-3z所确定,求证z对x的偏导加上z对y的偏导等于1 已知(Y+Z)除以X等于(X+Z)除以Y等于(X+Y)除以Z,求(X-Y-Z)除以(X+Y+Z) x-y/(z-x)(z-y) 一y-z/(x-y)(x-z) ＋z-x/(y-z)(y-x) x^-(y-z)^/(x+y)^-z^ 计算（x+y-z)(x-y-z) 计算：(x-y+z)(-x+y+z) (x+y-z)(x-y+z)=