The problem is to add two complex numbers: $(6 - i) + (-7 + 9i)$.

To add complex numbers, combine the real parts and the imaginary parts separately.

1. Real part: $6 + (-7) = -1$
2. Imaginary part: $-i + 9i = 8i$

So, the sum is: $-1 + 8i$

Answer: $-1 + 8i$

Would you like more details or have any questions about this solution?

Here are some additional related questions for further practice:

1. How would you subtract two complex numbers, such as $(4 + 3i) - (2 + 5i)$?
2. What is the modulus of a complex number like $-1 + 8i$?
3. How do you multiply two complex numbers, such as $(2 + i) \times (3 - 4i)$?
4. How would you find the complex conjugate of a number like $-1 + 8i$?
5. How do you divide one complex number by another, for example, $\frac{6 - i}{2 + i}$?

Tip: When adding or subtracting complex numbers, always handle real and imaginary parts separately for simplicity.