｛2x+5y=13z+1000 ｛3x+3z=9y ｛6y+8z+600=5x

｛2x+5y=13z+1000 ｛3x+3z=9y ｛6y+8z+600=5x 2X+5Y-13Z=1000 ;3X+3Z=9Y; 6Y+8Z-5X=-600 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 {x+y+z=1;x+3y+7z=-1;z+5y+8z=-2 x/10 = y/8 =z/9 求x+2y+3z/y-5z 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-2y-(x+y)]-x+(3y-10z)]=? kuai {2x+3y-4z=-5 x+y+z=6 x-y+3z=10 解方程组：x+y+z=4,x+y+2z=5,3x+y-z=6 2x+5y+4z=6,3x+y-7z=-4,x+y-z=? 5x+3y+2z=2011 4x+6y+7z=2012 求x+y+z