9, 6, 3, 0
a =Ist Term = 9.
Common difference is = T2 - T1 = 6 - 9 = -3.
The sequence is an Arithmetic Progression AP = a + (n-1)*d
Tn = a + (n-1)*d
Tn = 9 + (n-1)*(-3). Expand and simplify.
Tn = 9 - 3n +3.
Tn = 12 - 3n.
Hence the recursive formula is = 12 - 3n. Where n = position of term. n = 1, 2, 3, ..
