Find the ` 15^(th)` term of the series
` 3 - 6 +9 - 12 + …`

Explanation

To find the 15th term of the series \(3 - 6 + 9 - 12 + \ldots\), we can break it down into two parts: the arithmetic progression (AP) of the absolute values of the terms and the alternating signs.

### Step 1: Identify the pattern in the series
The series can be rewritten as:
\[ 3, -6, 9, -12, \ldots \]
The absolute values of the terms form an arithmetic progression (AP):
...