(2)2y+3=-4z 5y+6z=-7 (3)2x-3y=3 3x-2y=7
1.已知x:y:z=4:5:7,求:(一)2x+3y+z/5z; (二)x+y/y+z 非常急,
2x+5y+4z=6,3x+y-7z=-4,x+y-z=?
已知2x+5y+4z=6 3x+y-7z=-4求x+y-z
5x+3y+2z=2011 4x+6y+7z=2012 求x+y+z
已知x::y:z=3:4:5,(1)求x+y分之z的值;(2)若x+y+z=6,求x,y,z.
2X+Y+Z=10,X+2Y+Z=-6,X+Y+2Z=8 5X+4Y-3Y=13,2X-3Y+7Z=19,3X-Y=2X
试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)
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
x/2=y/3=z/5 x+3y-z/x-3y+z
2x+5y+4z=0,3x+y-7z=0,则x+y-z=?
解下列方程组(1)3x-y+z=3 2x+y-3z=11 x+y+z=12(2)5x-4y+4z=13 2x+7y-3z
已知3x=4Y,5Y=6Z,求 (1)x:y:z;(2)x+y/y+z.