To use the Associative Property to group like terms in the expression \( 9x + (2x + 3) \), we can rearrange the grouping of the terms.
Starting with the expression:
\[ 9x + (2x + 3) \]
we can regroup the terms as follows:
\[ (9x + 2x) + 3 \]
This groups the like terms \( 9x \) and \( 2x \) together. Therefore, the expression \( 9x + (2x + 3) \) can be grouped as \( (9x + 2x) + 3 \) using the Associative Property.