Answer
$_{14}P_8=121,080,960$
Work Step by Step
$_nP_r=\frac{n!}{(n-r)!}$
$n=14$ and $r=8$
$_{14}P_8=\frac{14!}{(14-8)!}=\frac{14!}{6!}$
But, $14!=14\times13\times12\times11\times10\times9\times8\times7\times(6\times5\times4\times3\times2\times1)=14\times13\times12\times11\times10\times9\times8\times7\times6!$
$_{14}P_8=\frac{14\times13\times12\times11\times10\times9\times8\times7\times6!}{6!}=14\times13\times12\times11\times10\times9\times8\times7=121,080,960$
