Let's simplify the given expression:

$(9y^3 - 2y^2 + 1) + (-5y^2 + 1 - 4)$

Step-by-step:

1. First, group like terms:
   • $9y^3$ (only term with $y^3$)
   • Combine the $y^2$ terms: $-2y^2 + (-5y^2) = -7y^2$
   • Combine the constant terms: $1 + 1 - 4 = -2$

So, the simplified expression is:

$9y^3 - 7y^2 - 2$

This is the final simplified form.

Would you like more details or have any further questions?

Here are 5 related questions:

1. How do you factor cubic polynomials?
2. What are the steps for simplifying expressions with exponents?
3. How do you perform polynomial long division?
4. What is the difference between adding and multiplying polynomials?
5. How do you find the roots of a cubic equation?

Tip: Always group like terms first when simplifying polynomials to avoid mistakes!