Chapter 2 - Reasoning and Proof - 2-3 Biconditionals and Definitions - Practice and Problem-Solving Exercises - Page 101: 10

Converse: If $|x|=3$, then $x=3$. The converse is not true, so the statement cannot be written as a biconditional. The number $-3$ is a counterexample that proves the converse false.

To write the converse of a conditional statement, write a new conditional statement that switches the hypothesis and conclusion.