Answer:
we have:
u(1) = 18
u(2) = 21 = 18 + 3
u(3) = 24 = 18 + 3.2
u(4) = 27 = 18 + 3.3
.......
=> the sequence has: u(1) = 18
d = 3
=> u(n) = 18 + 3(n - 1) = 3n + 15
so the recursive formula for the sequence is u(n) = 3n + 15
Step-by-step explanation:
