Answer:
Therefore, we conclude that R is an equivalence relation.
Step-by-step explanation:
We know that a relation on a set is called an equivalence relation if it is reflexive, symmetric, and transitive.
R is refleksive because we have that a+b = a+b.
R is symmetric because we have that a+d =b+c equivalent with b+c =a+d.
R is transitive because we have that:
((a, b), (c, d)) ∈ R ; ((c, d), (e, f)) ∈ R
a+d =b+c ⇒ a-b=c-d
c+f =d+e ⇒ c-d =e-f
we get
a-b=e-f ⇒ a+f=b+e ⇒((a, b), (e, f)) ∈ R.
Therefore, we conclude that R is an equivalence relation.
