Which property is demonstrated? 3[5(4)] + 3 = [3(5)]4 + 3

The expression changes from 3[5(4)] to [3(5)]4, which only changes how the factors 3, 5, and 4 are grouped. Their order stays the same, so this demonstrates the associative property of multiplication. The added 3 remains unchanged.

AI-written and checked against the verified answer.