Question 1139281
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You can't cancel the (n-2) and (n-4) in the denominator on the right; they are not factors.<br>
The denominator on the right is simply (n-2)-(n-4) = 2.<br>
Then write the n! on the left as n(n-1)(n-2)!; do some canceling of common factors; cross-multiply; and solve.