解方程组{x+2z=50；x+y+z=70；2z+y=50

解方程组x+y+z=30,3x+2y+z=50 解方程组{z=x+y 3x-2y-2z=-5 2x+y-z=3 解方程组：x-2y+z=-1,x+y+z=2,x+2y+3z=-1 解方程组 z=x+y 2x-3y+2z=5 x+2y-z=3 解方程组2x+y-z=7 x+y+z =1 2x-y-z=5 解方程组:2x+y+z=15 x+2y+z=16 x+y+z=17 解方程组x-4y+z=-3,2x+y-z=18,x-y-z=7. 解方程组{2x+3y+z=11,x+y+z=0,3x-y+z=-2. 解方程组{3x+y-z=4,2x-y+3z=12,x+y+z=6} x+z=y 7*x=y+z+2 x+y+z=14 解这个方程组、 x+y/2=z+x/3+y=z/4,...x+y+z=27.解方程组. 解方程组：x+y+z=4,x+y+2z=5,3x+y-z=6