The expression $-9a - 2(9a - 5)$ can be simplified as follows:

1. Distribute the $-2$ across the terms inside the parentheses:
   $-9a - 2(9a - 5)$
   = $-9a - 2 \cdot 9a + 2 \cdot 5$
   = $-9a - 18a + 10$

2. Combine like terms:
   $-9a - 18a + 10 = -27a + 10$

So, the simplified form is: $-27a + 10$

Do you have any questions or want more details on how this was done?

Here are 5 related questions:

1. How would the expression change if the $-9a$ term were positive?
2. How do you distribute when the sign outside the parentheses is positive?
3. What if the number inside the parentheses was more complex, like $9a + 3b - 5$?
4. How can you factor the final simplified expression $-27a + 10$?
5. Can you solve the equation if $-27a + 10 = 0$?

Tip: Always distribute carefully and combine like terms to simplify expressions easily.