Question

Let $R$ be a relation on $N$ defined by $x+2y=8$. Then the number of elements in the domain of $R$ is

Answer 1

Answer: 3

$R$ be a relation on $N$ defined by $x+2y=8$
$\therefore R=\left\{\left(2,3\right);\left(4,2\right);\left(6,1\right)\right\}$
$R=\left\{2,4,6\right\}$