The expression simplifies to:

$-4y^3 - 4y + 4$

Would you like a breakdown of how the terms were combined? Here are some related questions:

1. What are like terms, and how do you identify them?
2. Can terms with different powers of the same variable be combined?
3. What is the difference between combining like terms and simplifying an expression?
4. How does distributing multiplication affect combining like terms?
5. How can we solve equations after simplifying?

Tip: Always ensure that terms have the exact same variables and exponents before combining them.