 Multinomial theorem

For a nonnegative integer $n$,

The Multinomial Theorem is a generalization of the Binomial Theorem that describes how to expand expressions of the form \((x_1 + x_2 + \cdots + x_m)^n\), where \(x_1, x_2, \ldots, x_m\) are variables and \(n\) is a non-negative integer.