Here are some more I have problems with.

solve:
9

To solve the equation "9", there doesn't seem to be an equation given. However, if you only want to simplify or evaluate the expression "9", it is already in its simplest form.

If you are looking for potential operations you can perform on the number 9, here are a few:

1. Addition: You can add 9 to another number to get the sum. For example, 9 + 5 = 14.
2. Subtraction: You can subtract a number from 9. For example, 9 - 3 = 6.
3. Multiplication: You can multiply 9 by another number. For example, 9 x 2 = 18.
4. Division: You can divide 9 by another number (except zero). For example, 9 / 3 = 3.

If you have a specific equation or problem you'd like help with, please provide more information, and I'll be happy to assist you further.