For the following relation on the set {1,2,3,4,5,6,7,8,9,10,11,12}.

$Complete \space question \space is \space \\ For \space the \space following \space relation \space on \space the \space set \space \\ \space { \space \{1,2,3,4,5,6,7,8,9,10,11,12 \space \} \space }.\\ Relation \space is \space given \space by \space xRy \space \iff \space y=3x \space , \space then \space R \space = \space ? \space \\ Solution \space \\ Relation \space given \space \\ xRy \space \iff \space y=3x \space \\ Put \space x=1 \space and \space we \space get \space y \space = \space 3 \space \\ Put \space x \space = \space 2 \space and \space we \space get \space y \space = \space 6 \space \\ Put \space x \space = \space 3 \space and \space we \space get \space y \space = \space 9 \space \\ Put \space x \space = \space 4 \space and \space we \space get \space y \space = \space 12 \space \\ Now \space we \space cannot \space put \space x \space = \space 5 \space becouse \space we \space get \space y \space = \space 15, \space which \space not \space belong \space to \space set. \space \\ Hence \space R \space = \space \{ \space (1,3),(2,6),(3,9),(4,12) \space \}$