Are you sure there’s supposed to be a B’? It looks to me like you just need to calculate A’ = BAB^-1. That way, when you take A’ away, you get back to B instead of B’.
Are you sure there’s supposed to be a B’? It looks to me like you just need to calculate A’ = BAB^-1. That way, when you take A’ away, you get back to B instead of B’.