若2x-5y+4z=17,2x+10y+z=13,则x+y+z=?帮个忙,OK?

若4x=7y+5z,2x+y=z,则x:y:z的值为 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 若{x+3y+10z=0 则 (x+y-z)/(x-y+z) x/2=y/3=z/5 x+3y-z/x-3y+z (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai 2X+Y+Z=10,X+2Y+Z=-6,X+Y+2Z=8 5X+4Y-3Y=13,2X-3Y+7Z=19,3X-Y=2X 若3x+7y+z=5,4x+10y+z=3,则x+y+z=? 若x/3=y/2=z/5,则2x-3y-z/x-y+z= 2x+5y+4z=0,3x+y-7z=0,则x+y-z=? 已知2x+5y+4z=15.7x+y+3z=14 则x+y+z=? {2x+3y-4z=-5 x+y+z=6 x-y+3z=10 已知方程组4x-5y+2z=0 x+2y=3z 则x:y:z