x:z=2:5 y:z=3:10 x+5y+2z=78
x/2=y/3=z/5 x+3y-z/x-3y+z
{x+y+z=1;x+3y+7z=-1;z+5y+8z=-2
3x+2y+z=14 ,x+y+z=10,z+2x+3y=1 5
{2x+3y-4z=-5 x+y+z=6 x-y+3z=10
试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)
x/10 = y/8 =z/9 求x+2y+3z/y-5z
(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai
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+y=z 2x-3y+2z=5 x+2y-z=3
解方程组{z=x+y 3x-2y-2z=-5 2x+y-z=3
x+y-z=0 2x-3y+2z=5 x+2y-z=3
解方程组 z=x+y 2x-3y+2z=5 x+2y-z=3