1. **State the problem:** Solve the system of complex equations: $$z + (2 + i)w = 15i$$ $$(4 - i)z - 3w = ?$$ 2. **Identify the unknowns and equations:** We have two unknowns, complex numbers $z$ and $w$, and two equations. The second equation is incomplete, so we can only solve the first equation or express $z$ in terms of $w$. 3. **Rewrite the first equation:** $$z = 15i - (2 + i)w$$ 4. **Explanation:** Since the second equation is incomplete, we cannot solve for $z$ and $w$ uniquely. We express $z$ in terms of $w$ using the first equation. **Final answer:** $$z = 15i - (2 + i)w$$