2(x+y-z)-3(x-y+z)-5(x+y-z)+6(x-y+z) 计算

(y-x)/(x+z-2y)(x+y-2z)+(z-y)(x-y)/(x+y-2z)(y+z-2x)+(x-z)(y-z (x+y+z)^5-(x+y-z)^5-(x+z-y)^5-(z+y-x)^5, x/2=y/3=z/5 x+3y-z/x-3y+z x,y,z正整数 x>y>z证明 x^2x +y^2y+z^2z>x^(y+z)*y^(x+z)*z^(x+y) 1.（x+y-z)+(x-y+z)-(x-y-z) 2.2x-(3x-2y+3)-(5y-2) 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) (x+y-z)(x-y+z)= 因式分解：25x y^2 z^2 (x+y-z)-30xyz(z-x-y)^2+5x y z^3 (z-x-y) 化简(y-x)(z-x)/(x-2y+z)(x+y-2z)+（z-y)(x-y)/(x-2z+y)(y+z-2x)+(x (x-2y+z)(x+y-2z)分之（y-x)(z-x) + (x+y-2z)(y+z-2x)分之(z-y)(x-y) 如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y, {2x+3y-4z=-5 x+y+z=6 x-y+3z=10