Question

Let R be a relation on N defined by x + 2y = 8. The domain of R is

(a) [2, 4, 8]
(b) [2, 4, 6, 8]
(c) [2, 4, 6]
(d) [1, 2, 3, 4]

Answer 1

(c) {2, 4, 6}

x + 2y = 8
⇒ x = 8 $-$ 2y
For y = 1, x = 6
y = 2, x = 4
y = 3, x = 2
Then R = {(2,3),(4,2),(6,1)}
∴ Domain of R = {2,4,6}