If `P(5, r)=P(6, r-1),\ fin d\ rdot`

Explanation

To solve the equation \( P(5, r) = P(6, r-1) \), we will follow these steps:

### Step 1: Write the permutation formulas
The permutation formula \( P(n, r) \) is given by:
\[ P(n, r) = \frac{n!}{(n-r)!} \]
Using this, we can express \( P(5, r) \) and \( P(6, r-1) \):
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