In this case, we'll have to carry out several steps to find the solution.
Step 01:
Data:
12, -2, – 12, – 22...
arithmetic sequence = ?
Step 02:
arithmetic sequence:
an = a1 + (n - 1) d
a1 = 12
a2 = -2
d = a2 - a1 = -2 - 12 = -14
an = 12 + (n - 1) (-14)
The answer is:
an = 12 - 14 (n - 1)
