The solution set $x > 3$ in interval notation is expressed as:

$(3, \infty)$

This means that $x$ can take any value greater than 3, but not including 3 itself.

Would you like more details on this process or have any questions?

Here are 5 related questions to expand your understanding:

1. How would you express $x \geq 3$ in interval notation?
2. How would you express $x < 3$ in interval notation?
3. What is the interval notation for $x \leq 5$?
4. Can you express the inequality $2 < x \leq 7$ in interval notation?
5. How do we express all real numbers in interval notation?

Tip: When using interval notation, round brackets $()$ indicate that an endpoint is excluded, while square brackets $[]$ indicate that an endpoint is included.