Can somebody tell me if I've started this off right?

I need to use the Lagrange method to find the minimum distance from the point (1,2,3) to any point of the surface: $\displaystyle x + 2y - z = 2$

Let: $\displaystyle D^2=f(x,y,z)=(x-1)^2+(y-2)^2+(z-3)^2$

and

$\displaystyle g(x,y,z)=x+2y-z-2=0$

and then just carry on in the usual manner?