GDStash选择存档位置:2x+5y+4z=0 ,3x+y-7z=0,则x+y-z的值为多少？

来源：百度文库 编辑：查人人中国名人网 时间：2024/05/03 09:19:46
2x+5y+4z=0 ,3x+y-7z=0,则x+y-z的值为多少？请高手帮忙！谢谢！

2x+5y+4z=0(1)
3x+y-7z=0 (2)
(1)*3-(2)*2消去x，得13y-26z=0,得y=2z;
(2)*5-(1)消去y，得13x-39z=0,x=3z;
所以，x+y-z =3z-2z-z=0.

2x+5y+4z=0, 3x+y-7z=0.
x+y-z
=(2/13)*(2x+5y+4z)+(3/13)*(3x+y-7z)=0.

2x+5y+4z=0,3x+y-7z=0,则x+y-z=? 2x+5y+4z=0,3x+y-7z=0,则x+y-z=? 如果x/2=y/7=z/5,x,y,z都不等于0，则（x+y+z)/(3x-y)等于多少？ 已知3x-z=x+y+z=4x+2y-z,求x : y : z 若2x+5y+4z=0,3x+y-7z=0,则x+y-z 的值是___________? 2x+5y+4z=0 ,3x+y-7z=0,则x+y-z的值为多少？ 若2x+5y+4z=0,3x+y+7z=0,则x y-z值是多少? 13x+5y+9z=12.7 2x+4y+3z=4.7 x+y+z=? 2x+Y+3z=23,x+4y+5z=36,求X+2Y+3z~~~~ 若x,y ,z满足方程组1、3x+7y-x=3 2、4x+10y-z=2 求X+Y+Z的值