Use Cramer's rule to solve each system of equations. If D = 0, then use another method to determine the solution set. See Examples 5–7. 1.5x + 3y = 5 2x + 4y = 3

Key Concepts

Cramer's Rule

Cramer's Rule is a mathematical theorem used to solve systems of linear equations with as many equations as unknowns, provided the determinant of the coefficient matrix is non-zero. It expresses the solution in terms of determinants, allowing for a straightforward calculation of variable values. If the determinant is zero, the system may have no solution or infinitely many solutions, necessitating alternative methods.

Determinants

A determinant is a scalar value that can be computed from the elements of a square matrix and provides important information about the matrix, such as whether it is invertible. For a 2x2 matrix, the determinant is calculated as ad - bc, where a, b, c, and d are the elements of the matrix. A determinant of zero indicates that the matrix does not have an inverse, which is crucial for applying Cramer's Rule.

Alternative Methods for Solving Systems

When Cramer's Rule cannot be applied due to a zero determinant, alternative methods such as substitution, elimination, or matrix row reduction can be used to find the solution set. These methods involve manipulating the equations to isolate variables or simplify the system, allowing for the identification of solutions even when the system is dependent or inconsistent.