预备年级:解方程组{x=1 2x+3y=8 x+3y+4z=19 解方程组:{y=2x-7 5x+3y+2z=2 3x-
解方程组:x+y+z=4,x+y+2z=5,3x+y-z=6
解方程组:2x+3y+4z=20,x+y+z=7
解方程组x+2y-z=1 ,3x-3y+z=2,2x+3y+z=7和方程组x+y=-14,y+z=-7,x+z=19
解方程组{z=x+y 3x-2y-2z=-5 2x+y-z=3
解方程组 z=x+y 2x-3y+2z=5 x+2y-z=3
解方程组:x-2y+z=-1,x+y+z=2,x+2y+3z=-1
解方程组{3x+y-z=4,2x-y+3z=12,x+y+z=6}
解方程组x-4y+z=-3,2x+y-z=18,x-y-z=7.
x+y/2=z+x/3+y=z/4,...x+y+z=27.解方程组.
x:y:z=2:3:5解方程组 2x+3y-z=16
解方程组:x+2y+3z=80,x/2+y/3=z/4,
解方程组:{x/2=y/3=z/4 2x+y+z=22