Binomial theorem
In elementary algebra, the binomial theorem (or binomial expansion) describes the algebraic expansion of powers of a binomial. According to the theorem, the power ( x + y ) n {\displaystyle \textstyle (x+y)^{n}} expands into a polynomial with terms of the form a x k y m {\displaystyle \textstyle ax^{k}y^{m}} , where the exponents k {\displaystyle k} and m {\displaystyle m} are nonnegative integers satisfying k + m = n {\displaystyle k+m=n} and the coefficient a {\displaystyle a} of each term is a specific positive integer depending on n {\displaystyle n} and k {\displaystyle k} .