3(xx^2+y^3)

To simplify the expression \( 3(xx^2 + y^3) \), you can distribute the 3 into the parentheses:

\[ 3(xx^2 + y^3) = 3 \cdot xx^2 + 3 \cdot y^3 \]

Now simplify each term:

1. \( 3 \cdot xx^2 = 3x^{1+2} = 3x^3 \)
2. \( 3y^3 \) remains \( 3y^3 \)

So combining these, the simplified expression is:

\[ 3x^3 + 3y^3 \]

If you want to factor this further, you can factor out a 3:

\[ 3(x^3 + y^3) \]

Therefore, the final answer can be expressed as:

\[ 3(x^3 + y^3) \]