Identify Each of the Variables in the Binomial Probability Formula $P ( x ) = \frac { n ! } { ( n - x ) ! x ! } \cdot p ^ { x } \cdot ( 1 - p ) ^ { n - x }$

Essay

Identify each of the variables in the Binomial Probability Formula.
$P ( x ) = \frac { n ! } { ( n - x ) ! x ! } \cdot p ^ { x } \cdot ( 1 - p ) ^ { n - x }$ Also, explain what the fraction $\frac { n ! } { ( n - x ) ! x ! }$ computes.