The expression you provided is:

$10 \lt - (a - 9)$

To solve this inequality, let's follow these steps:

1. Start by distributing the negative sign on the right-hand side:

$10 \lt -a + 9$

2. Subtract 9 from both sides:

$10 - 9 \lt -a$

$1 \lt -a$

3. Multiply both sides by $-1$ to isolate $a$ (remember to reverse the inequality sign when multiplying or dividing by a negative number):

$-1 \gt a$

Thus, the solution is:

$a < -1$

Would you like more details or have any questions?

Here are 5 related questions:

1. What is the effect of multiplying or dividing inequalities by negative numbers?
2. How do you solve compound inequalities?
3. What are some real-world examples of using inequalities?
4. How do you graph inequalities on a number line?
5. How do inequalities differ from equations?

Tip: When solving inequalities, always remember to flip the inequality sign when multiplying or dividing by a negative number!