The task is to determine the real part of the complex number $z = 4 - i$.

In a complex number of the form $z = a + bi$, where $a$ is the real part and $b$ is the imaginary part, the real part is simply the value of $a$.

For $z = 4 - i$:

• The real part is $4$.

Answer: 4

Would you like further details or have any questions?

Here are some related questions to expand on this topic:

1. What is the imaginary part of $z = 4 - i$?
2. How do you find the modulus (absolute value) of a complex number?
3. What is the conjugate of the complex number $z = 4 - i$?
4. How would you represent $z = 4 - i$ in polar form?
5. Can you explain the difference between real and imaginary parts of a complex number?

Tip: In complex numbers, the real part is always independent of $i$, while the imaginary part is the coefficient of $i$.