Question

Como resolver essa operação com fatorial?

$\frac{5! 15!}{13! 7!}$

Answer 1

$\frac{5!15!}{13!7!}~=~\frac{5!.(15~.~14~.~13!)}{13!.(7~.~6~.~5!)}~=~\frac{1.(15~.~14~.~1)}{1~.~(7~.~6~.~1)}~=~\frac{15~.~14}{7~.~6}~=~\frac{210}{42}~=~\boxed{5}$