Let's simplify the expression step by step.

Given expression:
$-9a - 2(9a - 5)$

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

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

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

Would you like further details or have any questions?

Here are 5 related questions:

1. How do you factor expressions like $-27a + 10$?
2. Can you simplify $-3x - 4(2x + 7)$?
3. What is the difference between distributing and factoring?
4. How do you solve linear equations after simplifying them?
5. What is the next step if you were given an equation like $-9a - 2(9a - 5) = 0$?

Tip: Always apply the distributive property carefully by multiplying each term inside the parentheses.