1. Matrix Operations

2. What is a Matrix? This order of this matrix is a 2 x 3. columns rows
MATRIX: A rectangular arrangement of numbers in rows and columns.
The ORDER of a matrix is the number of the rows and columns.
Rows are read first, then columns.
The ENTRIES are the numbers in the matrix. Each entry is called an ELEMENT
When you read the position of an element in the matrix , you read the row first , then the column.
For example: the element “5” is in row 2 and column 3.
So we write it 2,3
This order of this matrix is a 2 x 3.
columns
rows

3. What is the order? (or square matrix) 3 x 3
(Also called a column matrix)
1 x 4
3 x 5 ( RECTANGULAR MATRIX)
(or square matrix)
2 x 2
4 x 1
(Also called a row matrix)

4. Matrix Addition
To add two matrices, they must have the same order. To add, you simply add corresponding entries.

5. = 7 7 4 5 = 7 5 7

6. Matrix Subtraction
To subtract two matrices, they must have the same order. You simply subtract corresponding entries.

7. 2-0
-4-1
3-8 -5 2 -5
8-3
0-(-1)
-7-1 5 -8 1 = =
1-(-4)
5-2
0-7 5 3 -7

8. Multiplying a Matrix by a Scalar
In matrix algebra, a real number is often called a SCALAR. To multiply a matrix by a scalar, you multiply each entry in the matrix by that SCALAR. A scalar is a numerical quantity.

9. -3 3 -2 6 -5
-2(-3)
-2(3) 6 -6
-12
-2(6)
-2(-5) 10