Final answer:
The expression (325 + b^4) cannot be simplified any further.
Step-by-step explanation:
To find an expression that is equivalent to (325 + b^4), we need to simplify the given expression as much as possible.
Since there are no like terms to combine, the expression cannot be simplified any further.
Therefore, the expression (325 + b^4) is already its simplest form and there is no equivalent expression among the given options:
A. 9a^10 + 68, B. 9a^10 - b^8, C. 9a^10 + 6a^5b^4 + b, and D. 9a^10 - 6a^5b^4 + b.