Insert six A.M.s between 15 and -13.

Explanation

To insert six arithmetic means (A.M.s) between 15 and -13, we can follow these steps:

### Step 1: Identify the first term (A) and the last term (A8)
The first term \( A \) is 15, and the last term \( A_8 \) is -13.

### Step 2: Determine the number of terms
We have the first term (15), six arithmetic means (A1, A2, A3, A4, A5, A6), and the last term (-13). This gives us a total of 8 terms.

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