Final answer:
The mathematical property being used is the Commutative Property of Multiplication, which states that changing the order of multiplication does not change the result.
Step-by-step explanation:
The property being illustrated by the equation 2 x 9 = 9 x 2 is the Commutative Property of Multiplication. This mathematical principle states that the product of numbers remains the same irrespective of the order in which they are multiplied. So, if we change the order from 2 times 9 to 9 times 2, the result (18) stays the same.
Here is the formula:
For any real numbers a and b, a x b = b x a.
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