If `^0P_5+5^9P_4=^(10)P_r ,` find the value of `rdot`

Explanation

To solve the equation \( ^0P_5 + 5 \cdot ^9P_4 = ^{10}P_r \), we will break it down step by step.

### Step 1: Understand the Permutation Formula
The permutation formula is given by:
\[ ^nP_r = \frac{n!}{(n-r)!} \]
where \( n \) is the total number of items, and \( r \) is the number of items to choose.
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