3x+y+z=31504x+10y+z=4200求x+y+z＝?

(x+y-z)(x-y+z)= 3x+y+z=31504x+10y+z=4200求x+y+z＝? X/10=Y/8=Z/9,则X+Y+Z/2Y-3Z 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z X=3z X+y+z=12 X+2y-2z=10 2x+z=10 x+y-z=4 3x-y-z=0 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? X+Y+Z=? x/y=(x+z)/(y+z)y/z=(x+y)/(x+z) x+2y+3z=23 y-z=5 x+2z=10 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)=? (4x-2y-z)-{5x-[8y-2z-(x+y)]-2(3y-10z)}=?好难啊 解方程组：{x(x+y+z)=6 {y(x+y+z)=9 {z(x+y+z)=10 x+y-z=3 y+z-x=5 z+x-y=7 求x,y,z 已知x+y+z=0求证x*x*x+y*y*y+z*z*z=3xyz 证明 ：x/(y+z)+y/(z+x)+z/(x+y)>=3/2其中 x,y,z>0 (y+z)/x=(z+x)/y=(x+y)/z求x+y-z/x+y+z的值