1. Matrices Continued… Guiding Question: How can we use matrices to find the value of inventory?

2. Matrix Product The product of two or more matrices Rules: – Matrices A and B can be multiplied ONLY if the number of columns in A equals the number of rows in B. (the inner dimensions must equal) – The product of an m x n and n x p matrix is an m x p matrix. (the outside dimensions will be the product) An m x n matrix A can be identified by using the notation A mxn

3. Is the product defined? P 2x5 R 4x3 Q 5x3 S 4x5 Use the matrices above to tell whether the product is defined: 1.PQ2. RS3. QP 4. SR 5. SQ6. RQ

4. Multiplying Matrices

5. 1.AB (together) 2.BA 3.AC 4.BC 5.CA

6. Step By Step Finding the Product

7. AB continued

8. Two stores held sales on their videos and DVDs, with prices as shown. Use the sales data to determine how much money each store brought in from the sale on Saturday. VideosDVDs Video World$8.95$11.95 Star Movies$7.50$12.50 Using Matrices for Inventory Total Sales FriSatSun Videos DVDs 23 40 31 48 25 42

9. Step By Step 1. Display the data in 2 matrices 2. Multiply the matrices to find the number of sales. Where do the Saturday Sales occur?

10. Homework :) Page 257: 2-14 even Have a great day!