Check if language is decidable
Define C = { $L | L$ is decidable by a turing machine with at most 42 states }

Notice that there is a finite amount of such languages, as there are a finite amount of turing machines with 42 states. for that reason, we have $C\ne\emptyset, \sum^*$

By Rice's theorem, the language $S=$ { $w | L(M_w) \in C$ } is undecidable. This language is precisely the language in question