$\"\"$

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The given expression is $\"\"$ .

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$\"\"$ (Permutation formula)

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$\"\"$ (Substitute $\"\"$ )

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$\"\"$ (Subtract: $\"\"$ )

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$\"\"$ (Factorial formula $\"\"$ ) $\"\"$ (Cancel common terms)

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$\"\"$ (Multiply: $\"\"$ ) $\"\"$

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The solution is 42.