For the AP ` -3, -7, -11, …` can we find directly `a_(30)-a_(20)` without actually finding `a_(30)` and `a_(20)` ? Give reason for your answer.

Explanation

To solve the problem, we need to find \( a_{30} - a_{20} \) for the arithmetic progression (AP) given by the sequence \(-3, -7, -11, \ldots\) without calculating \( a_{30} \) and \( a_{20} \) separately.

### Step-by-Step Solution:

1. **Identify the first term and common difference:**
- The first term \( a \) of the AP is \( -3 \).
- To find the common difference \( d \), we subtract the first term from the second term:
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