x的平方+y的平方+z的平方-2x+4y-6z+14
=x^2-2x+1+y^2+4y+4+z^2-6z+9
=(x-1)^2+(y+2)^2+(z-3)^2
x=1
y=-2
z=3
(x-y-z)^2009
=(1+2-3)^2009
=0