1. 4.4 Objectives
Day 1: Find the determinants of 2  2 and 3  3 matrices.
Day 2: Use Cramer’s rule to solve systems of linear equations.
Vocabulary
Determinant: The value of a square matrix. If the matrix is not square, then the determinant is undefined.
Coefficient matrix: A matrix whose elements are the coefficients from a system of equations.
Cramer’s rule: Used to solve a system of equations.

2. Example 1A: Finding the Determinant of a 2 x 2 Matrix
Find the determinant of each matrix.

3. Example 1A: Finding the Determinant of a 3 x 3 Matrix
Find the determinant of each matrix.

4. Example 1A: Finding the Determinant of a 3 x 3 Matrix
Find the determinant of

5. Pg , 14-17

6. Example 2: Using Cramer’s Rule for Two Equations
Use Cramer’s rule to solve each system of equations.

7. Solve using Cramer’s Rule

8. Pg 274 #2-9, 24
Pg 292 #30

9. You can use Cramer’s rule to tell whether the system represented by the matrix has one solution, no solution, or infinitely many solutions.