AIM: How do we perform basic
matrix operations?
DO NOW:

Describe the steps for solving a system of Inequalities

How do you know which region is shaded?
Section 3.5 – Basic Matrix
Operations

Using basic operations with matrices is simple, but
takes practice

Like we saw in 3.4, a MATRIX is an arrangement of
values in rows and columns

The dimensions of a matrix are indicated by the #
of rows and # of columns

m X n where m is number of rows and n is the
number of columns
Section 3.5 - Matrices

For examples:
 2 2


 3 2
 1 3 2 


2
6

7


3 0 2 


This is a 2 X 2 matrix
This is a 3 X 3 matrix
HOW DO WE READ MATRICES?
The Element in
the first row and
third column is
5
2 rows
3 columns
We read this as 2 by 3.
Section 3.5 – Adding,
Subtracting, Scalar Multiplication
of Matrices

In order to add or subtract, two matrices must
have the same dimensions!
Adding and Subtracting
Methods

Scalar Multiplication

Let Work on the
Worksheet
Homework for Section 3.5

Matrix Worksheet
p.191-192
#1-3,
7-9, 10-22(Even),
25, 26, 31, 34
Section 3.6 Multiply
Matrices
Section 3.6 – Multiplying
Matrices


Like we saw in 3.5, a MATRIX is an
arrangement of values in rows and
columns
The dimensions of a matrix are indicated
by the # of rows and # of columns


m X n where m is number of rows and n is the
number of columns
To multiply two matrices, one condition
must be met:

the # of columns of the 1st matrix must equal
the # of rows of the 2nd matrix
Section 3.6 - Matrices

For examples:
 2 2   1 4 

  4 0

 3 2 
 1 3 2   7 

 6 
2
6

7

  
 3 0 2   3 



Can these be
multiplied?