Question

Let $R$ be relation from $Q$ to $Q$ defined by $R=\left\{\right(a,b):a,b\in Qanda-b\in Z\}$.
Show that :
$(a,a)\in R$ for all $a\in Q$.

Answer 1

As $a-a=0\in Z$ (Integers)

$\Rightarrow (a,a)\in R$.