1. The problem asks to find the truth set of the letter $x$ in each case. The truth set of $x$ is the set of all values of $x$ that satisfy a given condition or equation. 2. To find the truth set, we need the specific conditions or equations involving $x$. Since the user did not provide any, we cannot determine the truth set without more information. 3. Generally, the truth set is found by solving the equation or inequality for $x$ and listing all values that make the statement true. 4. For example, if the condition is $x > 3$, the truth set is all real numbers greater than 3, i.e., $\{x \in \mathbb{R} \mid x > 3\}$. 5. Please provide the specific cases or conditions involving $x$ to find the truth sets.