Hi, it's been a while since I've attempted anything to do with vectors and I'm a little rusty at the moment.

The question is:

Fine a vector length $\displaystyle 2\sqrt{6}$ anti-parallel to $\displaystyle d = (-1,2,-1)$.

I thought that maybe the vector product would be the way forward but no idea where to start.

Any help would be greatly appreciated.

Thanks

Craig