Answer: a(n) = 5 - 3n
the sequence has:
a1 = 2
a2 = -1
a3 = -7
.........
we can see that: a2 - a1 = a3 - a2 = -3
=> the sequence is a arithmetic sequence
=> the distance between the numbers is d = -3
because this sequence is a arithmetic sequence
=> a(n) = a1 + (n - 1)d = 2 + (n - 1).(-3) = 5 - 3n
Explanation: