Answer :
a = 6, d = 3
f(n) = a + (n - 1)d = 6 + (n - 1)3 = 6 + 3n - 3 = 3 + 3n
f(n) = 3n + 3; n ≥ 1
a = 8, d = 6
f(1) = 8 and f(n) = f(n - 1) + 6
f(n) = a + (n - 1)d = 6 + (n - 1)3 = 6 + 3n - 3 = 3 + 3n
f(n) = 3n + 3; n ≥ 1
a = 8, d = 6
f(1) = 8 and f(n) = f(n - 1) + 6