The result of $-7 - 8$ is $-15$.

Would you like more details or have any further questions?

Here are some related questions you might find interesting:

1. What is the result of adding negative numbers like $-7 + (-8)$?
2. How do subtraction operations with negative numbers work on a number line?
3. What is the difference between adding and subtracting negative numbers?
4. How would you solve $-7 + 8$?
5. How do you handle subtraction involving negative and positive numbers in algebra?

Tip: When subtracting a positive number from a negative number, you are essentially moving further down the number line (in the negative direction).