Einstein relativity between 2 coordinates systems

[Atabold]

Homework Statement

Two coordinate events (24 s, 12 m) and (35 s, 25 m) occur on the x' axis of the system S'. At what speed must S' translate in order for the two events occur at the same point for S?
What is the x coordinate of this point?

Relevant Equations

V' = ( x'f — x'i ) / ( t'f — t'i )

I calculated the speed using the information provided through the above equation and finding V' = 1.2 m/s.

However, the first solution must be -1,2 m/s. I don't know how to reach it, any suggestion?

 

[PeroK]

Homework Statement: Two coordinate events (24 s, 12 m) and (35 s, 25 m) occur on the x' axis of the system S'. At what speed must S' translate in order for the two events occur at the same point for S?
What is the x coordinate of this point?
Relevant Equations: V' = ( x'f — x'i ) / ( t'f — t'i )

I calculated the speed using the information provided through the above equation and finding V' = 1.2 m/s.

However, the first solution must be -1,2 m/s. I don't know how to reach it, any suggestion?

Are you doing the standard, conventional transformation or the inverse? Which should it be?

 

[Atabold]

Are you doing the standard, conventional transformation or the inverse? Which should it be?

I have done the Lorentz transformation

 

[PeroK]

I have done the Lorentz transformation

The usual convention for the LT is to transform from the unprimed frame to the primed frame. You need the inverse transformation here, as you have data in the primed frame.