Question

даю 35 баллов. Вычислите : ​

Answer 1

$1)\frac{P_{9}-P_{7}}{P_{6}}=\frac{9!-7!}{6!}=\frac{7!*(8*9-1)}{6!}=\frac{6!*7*71}{6!}=7*71=\boxed{497} \\\\\\2)A_{5}^{4}-C_{5}^{3} =\frac{5!}{(5-4)!}-\frac{5!}{3!*(5-3)!}=5!-\frac{3!*4*5}{3!*2!}=5!-\frac{4*5}{1*2}=\\\\=1*2*3*4*5- 10=120-10=\boxed{110}$