x-y-2z=10; y-3z=-4 ;3x-y+5z=21; 解这个三元一次方程组.

2x+z=10 x+y-z=4 3x-y-z=0 (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? (4x-2y-z)-{5x-[8y-2z-(x+y)]-2(3y-10z)}=?好难啊 x+y/2=z+x/3=y+z/4 x+y+z=27 x+2y=3x+2z=4y+z 求x:y:z X/10=Y/8=Z/9,则X+Y+Z/2Y-3Z {2x+y=10 {x-y+z=4 {3x-y-z=0 x+2y+3z=10,x-y+4z=10,x+3y+2z=2 x+2y+3z=10,x-y+4z=10,x+3y+2z=2 4x+y+z=-3 2x+3y-4z=-10 x+2y-z=-1 x-y+4z=10,x+3y+2z=2,x+2y+3z=11. x+y+z=4 2x+3y-z=6 3x+2y+2z=10 x+2y+3z=10,4x+3y+2z=15则x+y+z= x+2y+3Z=10,4x+3y+2z=15,求x+y+z= 3x+2y+z=4 x+y+z=10 2x+3y-z=1 x+y+2z=5 2x-y-z=4 3x+y-3z=10 2x+y+3z=10,3x+4y+2z=15,则x+y+z= {2x+3y-4z=-5 x+y+z=6 x-y+3z=10