Question

F x is a prime number, then x + 1 is not a prime number.

A counterexample is x =

Answer 1

x=2

Explanation:

x=2

x+1=3

and 3 is a prime

Answer 2

A counterexample is x = 3

Explanation:

We are given that x is a prime number, and x + 1 is not a prime number. However consider the number 3. We know that 3 is a prime number, as it is present as factors of 1 and itself. However 3 + 1 = 4 - which falls into the category of a composite number, as it can divide into 2 * 2. Therefore your counterexample could be x = 3.