Question

calcule A9,3 ?
a) 27 b) 12 c) 54 d) 126 e) 504

Answer 1

$A_{9,3} = \frac{9!}{(9-3)!} = \frac{9!}{6!} = \frac{9.8.7.6!}{6!} =9.8.7=504$