(4x-2y-z)-{5x-[8y-2z-(x+y)]-2(3y-10z)}=?好难啊

(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai x/2=y/3=z/5 x+3y-z/x-3y+z 2X+Y+Z=10,X+2Y+Z=-6,X+Y+2Z=8 5X+4Y-3Y=13,2X-3Y+7Z=19,3X-Y=2X 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) {2x+3y-4z=-5 x+y+z=6 x-y+3z=10 {x+y+z=1;x+3y+7z=-1;z+5y+8z=-2 x/10 = y/8 =z/9 求x+2y+3z/y-5z 若4x-3y-6z=0,x+2y-7z=0,求代数式5x*5x+2y*2y-z*z/2x*2x-3y*3y-10z*10 (y-x)/(x+z-2y)(x+y-2z)+(z-y)(x-y)/(x+y-2z)(y+z-2x)+(x-z)(y-z x=y/z=z/3,x+y+z ＝12,求2x+3y+4z是多少, 1.（x+y-z)+(x-y+z)-(x-y-z) 2.2x-(3x-2y+3)-(5y-2) 已知3x-2y-5z=0,2x-5y+4z=0,且x,y,z均不为0,求3x*x+2y*y+5z*z/5x*x+y*y-