Final answer:
The property of addition illustrated in the equation (3x + 2) + 16 = 3x + (2 + 16) is the associative property of addition.
Step-by-step explanation:
The property of addition illustrated in the equation (3x + 2) + 16 = 3x + (2 + 16) is the associative property of addition. According to this property, the grouping of numbers being added does not affect the result.
In this case, the equation shows that regardless of whether we add (3x + 2) and 16 first or add 2 and 16 first and then add the result to 3x, we will get the same final sum. This property is true for ordinary numbers as well.