A=y(x-y)(x-z)+z(x-y)(z-x) 问：（1）将多项式A分解因式（2） x/2=y/3=z/4,求A/（xyz）的值

(x+y-z)(x-y+z)= X+Y+Z=? x/y=(x+z)/(y+z)y/z=(x+y)/(x+z) 填空a(x+y-z)+b(x+y-z)-c(x+y-z)=(x+y-z)乘以() 已知 x/(y+z)+y/(z+x)+z/(x+y)=1求 (x*x)/(y+z)+(y*y)/(x+z)+(z*z)/(x+y)=? (y+z)/x=(z+x)/y=(x+y)/z求x+y-z/x+y+z的值 x+y+z=12 x-y+z=2 x-z+y+a=90 x+y+a+z=100,求x y z a z+=x>y?++x: x-y/(z-x)(z-y) 一y-z/(x-y)(x-z) ＋z-x/(y-z)(y-x) x=y; y=z; z=x/y x^-(y-z)^/(x+y)^-z^ 计算（x+y-z)(x-y-z) 计算：(x-y+z)(-x+y+z) 求证tan(x-y)+tan(y-z)+tan(z-x)=tan(x-y)tan(y-a)tan(z-x) 用行列式的性质证明：y+z z+x x+y x y z x+y y+z z+x =2 z x y z+x x+y y+z y z x 这个怎么证? fangchengzu:X+Z=Y 7Z=X+Y+Z X+Y+Z=14 (x-2y+z)(x+y-2z)分之（y-x)(z-x) + (x+y-2z)(y+z-2x)分之(z-y)(x-y) + (y+z-2z)(x-2y+z)分之（x-z)(y-z)=?第三部分那个是 （y+z-2x)(x-2y+z)分之（x-z)(y-z) 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z