The expression you provided is:

$-13 + 9i$

This is a complex number, where:

• The real part is -13
• The imaginary part is 9i

You are asked to determine the real part of the result. The real part of the complex number is simply the coefficient of the non-imaginary part, which in this case is -13.

Thus, the real part of the expression is:

$\boxed{-13}$

If you need further clarification or have more questions, feel free to ask!

Related Questions:

1. What is the imaginary part of a complex number?
2. How do you add or subtract complex numbers?
3. How do you multiply complex numbers?
4. What is the modulus of a complex number?
5. What is the argument of a complex number?

Tip: When working with complex numbers, remember that the real part is just the number without the "i" and the imaginary part is the one that has "i".