The function you've written is $f(x) = 3x$.

Would you like to perform any specific operations with this function, such as finding its value for a specific $x$, determining its derivative, or something else? Let me know!

Here are some questions that could expand on the topic:

1. How do we find the derivative of $f(x) = 3x$?
2. What is the value of $f(x)$ when $x = 5$?
3. How can we evaluate the limit of $f(x) = 3x$ as $x$ approaches infinity?
4. What is the graph of $f(x) = 3x$ like? How does it behave?
5. What happens if we add a constant to the function, like $f(x) = 3x + 2$?

Tip: The function $f(x) = 3x$ is linear, which means its graph is a straight line with slope 3. The slope tells you how steep the line is.