The value of $f(-3)$ for the given piecewise function is $15$.

Would you like more details or have any questions? Here are five related questions to expand on this topic:

1. How would you evaluate $f(x)$ if $x = 4$?
2. What happens to the function $f(x)$ as $x$ approaches 3 from the left?
3. How do you find the domain of the given piecewise function?
4. How would you find the derivative of the piecewise function?
5. What is the behavior of $f(x)$ for large positive and large negative values of $x$?

Tip: When dealing with piecewise functions, always check which part of the function applies to the given value of $x$ before evaluating.