How does the Expand Master and Build Polynomial Equations Calculator work?

Free Expand Master and Build Polynomial Equations Calculator - This calculator is the ultimate expansion tool to multiply polynomials. It expands algebraic expressions listed below using all 26 variables (a-z) as well as negative powers to handle polynomial multiplication. Includes multiple variable expressions as well as outside multipliers. Also produces a polynomial equation from a given set of roots (polynomial zeros).
* Binomial Expansions c(a + b)^{x}
* Polynomial Expansions c(d + e + f)^{x}
* FOIL Expansions (a + b)(c + d)
* Multiple Parentheses Multiplications c(a + b)(d + e)(f + g)(h + i)

This calculator has 2 inputs.

What 1 formula is used for the Expand Master and Build Polynomial Equations Calculator?

a(x + y)^{n} = aΣ_{[k = 0 to n]}C(n,k) x^{n-k}y^{k}