1. 3.5 Perform Basic
Matrix Operations
Algebra II

2. Matrix (matrices) DEFINITION Row 1 Row 2 Row 3 Row m Column 1 Column 2

3. Example: Find the dimensions.
A matrix of m rows and n columns is called a matrix with dimensions m x n.
Example: Find the dimensions.
2 X 3
3 X 3
2 X 1
1 X 2

4. PRACTICE: Find the dimensions.
3 X 2
2 X 2
3 X 3
1 X 2
2 X 1
1 X 1

5. ADDITION and SUBTRACTION of
MATRICES

6. To add matrices, we add the corresponding elements
To add matrices, we add the corresponding elements. They must have the same dimensions.
A + B

7. When a zero matrix is added to another matrix of the same dimension, that same matrix is obtained.

8. To subtract matrices, we subtract the corresponding elements
To subtract matrices, we subtract the corresponding elements. The matrices must have the same dimensions.

9. PRACTICE PROBLEMS:

10. ADDITIVE INVERSE OF A MATRIX:

11. Find the additive inverse:

12. Scalar Multiplication:
We multiply each # inside our matrix by k.

13. Examples:

14. What are your
QUESTIONS?

15. Solving a Matrix Equation
Solve for x and y:
Solution
Step 1: Simplify

16. Scalar Multiplication:

17. 6x+8=26
6x=18
x=3
10-2y=8
-2y=-2
y=1

18. Properties of Matrix Operations p. 201
Let A,B, and C be matrices with the same dimension:
Associative Property of Addition (A+B)+C = A+(B+C)
Commutative Property of Addition A+B = B+A
Distributive Property of Addition and Subtraction S(A+B) = SA+SB S(A-B) = SA-SB
NOTE: Multiplication is not included!!!

19. Questions???!!!!

20. Assignment