Question

I need help on this question

Answer 1

Recall the permutation formula: nPr = n!/(n-r)!

In this question, n=9 and r= 4

Let's plug in those values into the formula

9!/(9-4)! = 9!/5! = 3024

The final answer is 3024!

Answer 2

$_9P_4=\frac{9!}{5!}=\frac{9*8*7*6*(5*4*3*2*1)}{(5*4*3*2*1}=9*8*7*6*5=3024$