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. (x+y)n=a0xny0+a1xn−1y1+a2xn−2y2+…+anx0yn Each of the terms is written in the form axbyc. 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.