X+Y+Z=10 2X+3Y-Z=20 2X+5Y-7Z=25 就算这个方程式无解也列出过程

3X+2y+z=20 x+y+z=10 Y=3X 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 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=5,2x+3y+z=10,x-2y-z=20求方程组 x+y-z=5 2x+3y+z=10 x-2y-z=20 速解, X=3z X+y+z=12 X+2y-2z=10 2x+z=10 x+y-z=4 3x-y-z=0 求{x+y-z=5；2x+3y+z=10；x-2y-z=20中x、y、z的值, (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? x+2y+3z=23 y-z=5 x+2z=10 证明 ：x/(y+z)+y/(z+x)+z/(x+y)>=3/2其中 x,y,z>0 (4x-2y-z)-{5x-[8y-2z-(x+y)]-2(3y-10z)}=?好难啊 x/2=y/3=z/5 x+3y-z/x-3y+z x+y/2=z+x/3=y+z/4 x+y+z=27 若x+y+z=3y=2z,则x/x+y+z=? x+2y=3x+2z=4y+z 求x:y:z {2x+y=10 {x-y+z=4 {3x-y-z=0