DefinitionCramer's law: Cramer's law is a solution to the decision of a system of equations. It gives the formula for solving the equation of the ratio of determinants whose elements are the coefficients of the equation. Cramer's law can be used when the system of equations has only one solution and the order of the coefficient matrix is non-zero. I, in the context of mathematics, engineering, physics) - Mathematics for solving systems of equations. Note: In mathematics, Cramer's law is an exact formula used to solve a system of linear equations with multiple unknowns and is valid as long as the system has specific problem solutions.