{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