Introduction:
Adding and subtracting integers can be done using a number line. It helps us visualize the operation and understand the concept better. In this case, we want to add -5 and (-4) and then subtract 9 from the sum. Let's go step by step to solve this problem.

Step 1: Add -5 and (-4):
To add -5 and (-4), we start at 0 on the number line and move 5 units to the left to reach -5. Then, from -5, we move another 4 units to the left to reach -9.
So, the sum of -5 and (-4) is -9.

Step 2: Subtract 9 from the sum:
Now, we have to subtract 9 from the sum we obtained in step 1, which is -9. To do this, we move 9 units to the left from -9 on the number line.
After subtracting 9, we end up at -18.

Answer:
The final result of the expression -5 + (-4) - 9 is -18.

Conclusion:
Adding and subtracting integers using a number line can help us visualize the operations and understand the concept better. In this case, we added -5 and (-4) to get -9, and then subtracted 9 from -9 to get the final result of -18. By following the steps and using the number line, we can solve similar problems involving addition and subtraction of integers.

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