The factorial of a number is the product of all positive integers less than or equal to that number. So, we have:
$$\frac{5 ! \cdot 7 !}{9 !} = \frac{(5 \cdot 4 \cdot 3 \cdot 2 \cdot 1) \cdot (7 \cdot 6 \cdot 5 \cdot 4 \cdot 3 \cdot 2 \cdot 1)}{(9 \cdot 8 \cdot 7
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