This is an expensive hotel is incorrect?
Це дорогий готель would be (technically) a more correct translation of your sentence. Added.
This hotel is expensive -> Цей готель дорогий ("This hotel" is the subject)
This is an expensive hotel -> Це дорогий готель ("This" is the subject)
I would say it is a missing alternative.
The audio sounds odd - I have played it over many times and all I can hear is "цей готень дорогий". I guessed it was готель from context of the previous examples in this module.