The binomial theorem states that when a power of a binomial $(x+y{)}^n,$ is expanded and $n$ is a natural number, it can be written as a sum of terms. $$\begin{array}{c}(x+y{)}^n=a_0{x}^n{y}^0+a_1{x}^{n-1}{y}^1+a_2{x}^{n-2}{y}^2+\dots +a_n{x}^0{y}^n\end{array}$$ Each of the terms is written in the form $a{x}^b{y}^c.$ In these terms, $b$ and $c$ are whole numbers and $b+c=n.$ The value of $a$ is found as term number $b$ on row number $n$ in Pascal's triangle.