Polynomial expansion is the process of expressing a polynomial in a simplified form by multiplying out its factors. For example, when expanding the expression (x + 2)(x + 3), you distribute each term in the first factor by each term in the second factor, resulting in x^2 + 5x + 6. This technique helps in simplifying calculations and understanding the behavior of polynomials. The most common method for polynomial expansion is the distributive property, which allows for systematic multiplication. Another useful tool is the binomial theorem, which provides a formula for expanding expressions of the form (a + b)^n. This theorem simplifies the process, especially for higher powers.