解方程 x(x+y+z)=6 y(x+y+z)=12 z(x+y+z)=18

解方程组{x(x+y+z)=6,y(x+y+z)=12,z(x+y+z)=18 (x+y-z)(x-y+z)= 解方程{3x -y+z=4 2x+3y-z=12 x+y+z=6 X+Y+Z=? 3x-y+z=3 2x+y-3z=11 x+y+z=12 解方程 f(x,y,z,w)=x*(x+y)*(x+y+z)*(x+y+z+w) 解方程组 x+y+z=-7 x-y=12 x+y-z=6 x y z x+y--- = --- = ---- ----y+Z z+x x+y ,求 z 的值 .求 x+y---- 如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y, 已知x+y-z/z=x-y+z/y=-x+y+z/x,且xyz不等于0,求分式[(x+y)(x+z)(y+z)]/xyz 若z分之x+y+z=y分之x-y+z=x分之-x+y+z,求xyz分之(x+y)(y+z)(z+x) y+z÷x=Z+X÷y=X+Y÷z,X+Y+Z不等0求X+Y-Z÷X+Y+z值