①2x+y-z=2 ②x+2y=5 ③x-y+2z=-7

{5X+Y+Z①X+5Y+Z=-2②X+Y+5Z=10③ x/2=y/3=z/5 x+3y-z/x-3y+z 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) 已知x/2=y/4=z/7,求①x：y：z.②若2x+y+3z=58,分别求x,y,z的值.③求x+y/x+z的值. (x+y-z)^2-(x-y+z)^2=? x,y,z为实数 且(y-z)^2+(x-y)^2+(z-x)^2=(y+z-2x)^2+(x+z-2y)^2+(x+y {x+y+z=1;x+3y+7z=-1;z+5y+8z=-2 x,y,z为实数且(y-z)平方+(x-y)平方+(z-x)平方=(y+z-2x)平方+(z+x-2y)平方+(x+y- 分解因式:f(x,y,z)=x^2(y-z)+y^2(z-x)+z^2(x-y) 2x+4y-3z=9① 3x-2y-4z=8② 5x-6y-5z=7③ 2x+4y+3z=9① 3x-2y+5z=11② 5x-6y+7z=13③ x+y+z=2 ① 2x+3y+z=38 ① x+y=3 3x-y-4z=5 ② 3x+4y+2z+56 ② y+z=5