1. PreCalculus Section 14.3 Solve linear equations using matrices
[A] [Z] = [A] =
[A] · [I] = [A]
· 𝟏 0 0 𝟏 =
[A] · [A]-1 = [I]
· −𝟑/𝟕 𝟓/𝟏𝟒 𝟐/𝟕 𝟏/𝟕 = 𝟏 𝟎 𝟎 𝟏
Note: many of the properties of real numbers and matrices are similar.
Real numbers a + 0 = a a · 1 = a a(1/a) = 1

2. Linear equations and matrix equations can be solve in similar fashions.
AX = B
X =
A-1 A X = A-1 B

3. Solve the matrix equation

4. A system of linear equations can be written as a matrix equation.
5x + 4y = -2
2x + 3y = -5

5. Solve the system
2x - y + z = 3 3x + 2y – 4z = 23 x – 3y – 2z = 14

6. Page 536 problem 25

7. Assignment
Page 534 Problems 2,4 10,12,14,16,23,26a