Тема факториал решить примеры

$1) \ \frac{h(h-1)(h-2)(h-3)(h-4)}{(h-3)!} = \frac{h(h-1)(h-2)(h-3)(h-4)}{1*2*...*(h-4)*(h-3)} =\\ \frac{h(h-1)(h-2)}{1*2*...*(h-5)} = \frac{h!}{(h-5)!(h-3)!}$

$2) \ \frac{10! - 8!}{89} = \frac{8!(9*10 -1)}{89} = 8! = 40320\\\\ 3) \ \frac{5! + 6!}{4!} = \frac{4!(5 +5*6)}{4!} = 35\\\\ 4) \ A^{m-5}_{m-1} = \frac{(m-1)!}{(m-1-m+5)!} = \frac{(m-1)!}{4!} = \frac{(m-1)!}{24} \\\\$