# Choosing the sign for speed in Lorentz transformations

I am studying the Lorentz transformations and while I [believe] I understand the principle of it (you’re sorta “translating” from one frame of reference to the other), I am having a lot of trouble understanding when we are supposed to use

$$x_{B} = \gamma(x_{A} - v_{xBA}t_{A})$$

Vs

$$x_{A} = \gamma(x_{B} + v_{xAB}t_{B})$$

While I am well aware that one relative speed from a referential is the negative of the other referential, I cannot understand how I can choose which is which.

Edit: is it because by doing the negative speed it (if $$v_{xAB} = - v_{xBA})$$ makes up for it and it comes down to the same formula?