1. Warm-Up 3) 1)
4) Name the dimensions 2)

2. Multiplying Matrices x

3. In order to multiply matrices...
A • B = AB
m x n
n x p
m x p
Ex 1.
Can you multiply? What will the dimensions be? A B AB
2 x 3
3 x 4
2 x 4 AB A B
5 x 3
5 x 2
Not possible

4. How to multiply... ac ad =
2 x 1
1 x 2
2 x 2

5. How to multiply... ac ad = bc bd
2 x 1
1 x 2
2 x 2

6. Ex. 1

7. Ex. 2
Find AB
-16
+ 1
-12 +2
-15
-10 =
- 2
- 4 -2
- 4

8. Ex. 3
Find BA

9. How to multiply... ag
+bi
+ck ah
+bj
+cm =
2 x 3
3 x 2
2 x 2

10. 2 x 3 3 x 2 2 x 2 = How to multiply... ag +bi +ck ah +bj +cm dg +ei
+fk dh
+ej
+fm
2 x 3
3 x 2
2 x 2

11. Ex. 4 -1(4) +5(6) -1(-3) +5(8) -4 + 30 3 + 40 5(4) +2(6) 5(-3) +2(8)20
+12
-15
+ 16 =
+ -24
+ -32
0(4)
+-4(6)
0(-3)
+-4(8) 26 43 32 1
-24
-32

12. If we are multiplying matrices, we multiply each row of the first matrix by each column in the second matrix!!
multiply each row of the first matrix by each column in the second matrix!! + + 1 + + 2 + + 1 + +

13. 2 X 3 3 X 3 2(3)+(-3)(8)+5(-3) 2(9)+(-3)(0)+ 5(1) 2(1)+(-3)(-4)+ 5(5)
-1(3)+(6)(8)+8(-3)
-1(9)+(6)(0)+ 8(1)
-1(1)+(6)(-4)+ 8(5)

14. Ex. 5

15. What are your questions?

16. Assignment
Westside Booster Club
# 6 a-d