Answer:
See below
Step-by-step explanation:
To write informal negations, change the existential quantifiers "some, there exists" for universal quantifiers "All, for every" and viceversa. Then write the informal negation of the statement after the quantifiers:
1) Some suspicions were unsubstantiated.
2) Some suspicions were substantiated.
3) All suspicions were substantiated.
4) No suspicions were unsubstantiated. Equivalently, Every suspicion was substantiated.
5) No suspicions were substantiated. Equivalently, Every suspicion was unsubstantiated.