math
posted by judy williams .
. Prove that x  y = y – x; for all integers x and y.

X  Y =  Y  X,
X + (Y) = Y + (X)..
Commutative Property: The order of addition does not matter.
a + b = b + a.
posted by judy williams .
. Prove that x  y = y – x; for all integers x and y.
X  Y =  Y  X,
X + (Y) = Y + (X)..
Commutative Property: The order of addition does not matter.
a + b = b + a.