(A2-4)  Here's the transformation from Nefertit's to Cormorant's frame of reference: 

Now write down the transformation equation that will convert a coordinate xC, measured at time tC in Cormorant’s frame of reference, into Nefertiti’s frame of reference. Just be careful to remember that if Cormorant is moving towards Nefertiti’s right with velocity u, then in Cormorant’s reference frame, she is moving towards his left, with a velocity -u.