Question

If R is a relation on the set A = {1, 2, 3, 4, 5, 6, 7, 8, 9} given by x R y ⇔ y = 3 x, then R =
(a) {(3, 1), (6, 2), (8, 2), (9, 3)}
(b) {(3, 1), (6, 2), (9, 3)}
(c) {(3, 1), (2, 6), (3, 9)}
(d) none of these

Answer 1

(d) none of these

The relation R is defined as
$$\begin{gathered} R=\left\{\left(x,y\right):x,y\in A:y=3x\right\} \\ \Rightarrow R=\left\{\left(1,3\right),\left(2,6\right),\left(3,9\right)\right\} \end{gathered}$$