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Question
Compute:
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Solution
\[\frac{11! - 10!}{9!} = \frac{11 \times 10 \times 9! - 10 \times 9!}{9!} \left[ \because n! = n(n - 1)! \right]\]
\[ = \frac{9!(110 - 10)}{9!}\]
\[ = 100\]
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