The expression to simplify is:

$-3(w+3) - 2(w+6)$

Let's break it down step by step.

1. Distribute the -3 and -2 through the parentheses: $-3(w) - 3(3) - 2(w) - 2(6)$

This gives us: $-3w - 9 - 2w - 12$

2. Now, combine the like terms: $-3w - 2w = -5w$ $-9 - 12 = -21$

So, the simplified expression is: $-5w - 21$

Let me know if you need further clarification or have any other questions!

Here are some related questions to explore:

1. How do you simplify an expression with more than two terms?
2. What is the distributive property, and how is it used in this example?
3. How do you solve an equation involving expressions like this one?
4. What are other ways to combine like terms effectively?
5. What happens if there is a negative sign before a variable or term?

Tip: Always double-check the signs when distributing, as it's easy to make mistakes with negative numbers.