(X+5)/(Y+5)=Z+150
x/2=y/3=z/5 x+3y-z/x-3y+z
(x+y+z)^5-(x+y-z)^5-(x+z-y)^5-(z+y-x)^5,
{x+y+z=1;x+3y+7z=-1;z+5y+8z=-2
一道数奥题,(x+y-z)²+(y+z-4)=-|z+x-5|
已知3X=4X,5Y=6Z求X+Y:Y+Z
(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai
{5X+Y+Z①X+5Y+Z=-2②X+Y+5Z=10③
若x+3y+5z=10,5x+z+3y=8,x+y+z=?
{2x+3y-4z=-5 x+y+z=6 x-y+3z=10
3x+7y+z=5 ,4x+10y+z=6 ,x+y+z=
解方程组x+y-z=-5,x-y-z=1,x-y+z=15
2x+5y+4z=0,3x+y-7z=0,则x+y-z=?