It is the commutative property of addition.
Identity Property of Addition
Identity.
Zero is the additive identity.
The property that 1 is the identity for multiplication.
Identity Property
symmetric property
Assuming that there is no significance in the first X being upper case and the second in lower case, it is an IDENTITY.
Commutative Property of Addition
The commutative property of addition
the commutative property of addition
The additive property.
The commutative property