3x+4y-5z=0求解答,x,y,z的值

已知{3x+4y+5z=0,2x+3y-4z=0,求x+y+z/x-y+z的值. 已知2x+3y-4z=0,3x+4y+5z=0,求x+y+z/（除以）x-y+z的值. 已知2x+3y-4z=0,3x+4y+5z=0,求x+y+z/x-y+z的值. 2x+3y-4z=0,3x+4y+5z=0,求x+y-z/x-y+z的值 已知x+4y+3z=3x-2y-5z=0,求x+2y-z/2x-3y+7z的值 方程组｛4x-3y-3z=0,x-3y+z=0,(x.y.z不等于0),求x/z和y/z的值? 4x-3y-3z=0 x-3y+z=0 并且X Y Z不等于0 求x:z 和y:z的值 已知2x+3y-4z=0,3x+3y+5z=0,求x+y+x/x-y+z的值 已知x,y,z满足方程组：4x-5y+2z=o;x+4y-3x=0,求x:y:z的值 x/3=y/4=z/5,求x+y+z/3x-2y+z的值, 若x/3=y/4=z/5,求x+y+z/3x-2y+z的值. 若x/2=y/3=z/4不等于0,求x+y+z/x+y-z的值