Question

Fatorial: Calcule: a) 15!13!/14!12! b) 12!3!/15!c) (3!-0!)!/3!2!

Answer 1

               $\frac{15!13!}{14!12!} = \frac{15.14!13.12!}{14!12"} =15.13 =195 \\ \\ \frac{12!3!}{15!} = \frac{12!3!}{15.14.13.12!} = \frac{3.2.1}{15.14.13} = \frac{1}{455}$

               $\frac{3!-0!}{3!2!} = \frac{3.2.1-1}{3.2.1.2.1} = \frac{5}{12}$