Let R be a relation on set N of natural numbers defined by R = {(a, b) : a, b ∊ N, a + 3b = 12} (or a R b : a + 3b = 12).
Find (i) R in Roster form (ii) Domain of R (iii) Range of R.
The given relation is aRb : a + 3b  = 12
      Â
When           Â
             Â
             Â
                   ...........................
      Â
                  ...................................
                  a = 9, Â
                  a = 10, Â
                   a = 11,Â
For           Â
Hence, Â Â Â Â Â Â Â Â Â Â R = {(3, 3), (6, 2), (9, 1)}
(ii) Â Â Domain of R = {3, 6, 9}
(iii) Â Â Range of R = {3, 2, 1}
          Â
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