2x+3y-z=11 2x+y-5z=8 -2x+7y+z=19 怎么求!简洁一些~

已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? x/2=y/3=z/5 x+3y-z/x-3y+z {x+y+z=1;x+3y+7z=-1;z+5y+8z=-2 2x+3y-z=11 2x+y-5z=8 -2+7y+z=19 (4x-2y-z)-{5x-[8y-2z-(x+y)]-2(3y-10z)}=?好难啊 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+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z X/10=Y/8=Z/9,则X+Y+Z/2Y-3Z x+Y+Z=1 X+3Y+7Z=-1 X+5Y+8Z=2x+Y+Z=1X+3Y+7Z=-1X+5Y+8Z=2 三元一次方程组题目x+y-z=11 y+z-x=5 x-y+z=1x+y=4 y+z=3 x+z=5若已知x-3y+2z=0 2x+3y-8z=0, 且xyz≠0,则x:y:z= x:y:z=3:4:5 2x-3y+2z=8 x-y-2z=? {x+y+z=1 x-2y+3z=5 2x-3y-3z=-8 x+y+z=-1 4x-2y+3z=5 y-z=8-2x {x+y+z=1 {x+3y+7z=-1 {x+5y+8z=2 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian 1.{x:y:z=3:4:5 2x+3y-5z=-142.{x-y-z=-1 3x+5y+7z=11 4x-y+2z=-13.{x+y=1 x+z=0 2x+y+2z=44.{x-y+z=-3 2x-y-z=-2 -3x+y+z=-15.{x-y+z=-3 3x+y-4z=6 2x+y-z=36.{x-2y+5z=16 2x+y-5z=7 2x-y+z=38 x-y-z=-1 3x+5y+7z=11 4x-y+2z=-1 分别求出x=?y=?z=?