I'm not sure how to go about solving this.
I tried this:
Suppose L is a Turing decidable language. Turing Machine M1 is a decider of L and M2 is a decider of the complement L We construct a TM U that simulates M1 and M2 on a word w. For any word w in complement L (this is infinite as it is the set of all possible words), M1 will always reject but M2 will always accept w. However, we cannot test this for all words in complement L as it is infinitely large, therefore it is undecidable.
I'm not sure if that is even remotely correct, would really appreciate some guidance on obtaining the correct answer