In its simplest form, a polynomial is a mathematical equation that involves a sum of powers in one or more variable, all multiplied by coefficients. In such equations, variables and numbers on both sides of the equal sign are considered polynomials. For example, by expanding out the expression (x - 2)³ (or multiplying out the equation) we discover that (x - 2)³ = x³ - 6x² + 12x - 8, which is a polynomial equation.