Let's solve the expression given in the image:

We are asked which expression is equivalent to $(7 + 4i) + (8 + i)$.

To simplify this:

1. Combine the real parts: $7 + 8 = 15$.
2. Combine the imaginary parts: $4i + i = 5i$.

Thus, the expression simplifies to $15 + 5i$.

So, the correct answer is:

15 + 5i

Let me know if you need more details or have any other questions!

Here are some related questions:

1. How do you add complex numbers?
2. What is the difference between real and imaginary numbers?
3. How do you subtract complex numbers?
4. What is the conjugate of a complex number?
5. What is the modulus of a complex number?

Tip: When adding or subtracting complex numbers, always group real parts and imaginary parts separately!