5y(y²-3)(y²+3)

To simplify the expression \( 5y(y^2 - 3)(y^2 + 3) \), we can leave it in its factored form, or we can expand it.

1. Factored Form: It's already in a factored state: \[ 5y(y^2 - 3)(y^2 + 3) \]

2. Expansion: We can expand it by first expanding \( (y^2 - 3)(y^2 + 3) \) using the difference of squares: \[ (y^2 - 3)(y^2 + 3) = y^4 - 9 \] Now, substitute this back into the expression: \[ 5y(y^4 - 9) \] Distributing \( 5y \): \[ 5y^5 - 45y \]

Thus, the expanded form of the expression is: \[ 5y^5 - 45y \]

In summary, the expression \( 5y(y^2 - 3)(y^2 + 3) \) can be left in its factored form \( 5y(y^2 - 3)(y^2 + 3) \) or expanded to \( 5y^5 - 45y \).