9、若3x+7y+z=315,4x+10y+z=420,则x+y+z=________________.
若{x+3y+10z=0 则 (x+y-z)/(x-y+z)
知3x+7y+z=315,4x+10y+z=420,求x+y+z=?
已知3x+7y+z=315和4x+10y+z=420,求x+y+z
若3x+7y+z=5,4x+10y+z=3,则x+y+z=?
谢了3x+7y+z=315 4x+10y+z=420
已知,方程组:4x-3y-7z=0 x+2y=10z 则(x-y+z)÷(x+y+z)=——
(x+y-z)(x-y+z)=
已知2x+3y-4z=7 3x-2y+z=3 x+5y+9z=20 则 x+y+z= 若x :y :z=2 :3 :7
若x-2y+4z=1,x+3y-7z=0,则y:z=?
若4x-3y-6z=0,x+2y-7z=0,求代数式5x*5x+2y*2y-z*z/2x*2x-3y*3y-10z*10
已知3X+7Y+Z=6 4X+10Y+z=7 求X+Y+Z=?
2x+5y+4z=0,3x+y-7z=0,则x+y-z=?