Find the sum of first `17` terms of an AP whose 4th and 9th terms are `-15` and `-30`, respectively.

Explanation

To find the sum of the first 17 terms of an arithmetic progression (AP) where the 4th term is -15 and the 9th term is -30, we can follow these steps:

### Step 1: Use the formula for the nth term of an AP
The formula for the nth term of an AP is given by:
\[ a_n = a + (n - 1)d \]
where:
- \( a \) is the first term,
- \( d \) is the common difference,
...