1. Two matrices can be added if they have the same dimensions. To add two matrices, add their corresponding elements.

2. Find Example 2-1a

3. Find 2  2 2  3 Matrices cannotbe added. Example 2-1b

4. Find Answer: Example 2-2a

5. To multiply a matrix by a scalar, multiply every element by the scalar.

6. Example 2-4a

7. 8 12 -6 3 -4 0 0 -3 9 14 -4 3 Example 2-5a

8. Pg 168 Matrix multiplication is defined only if the number of columns of the first matrix is equal to the number of rows of the second matrix.

9. Determine whether the product of is defined. If so, state the dimensions of the product. A • B = AB 3  4 4  2 3  2 The inner dimensions are equal so the matrix product is defined. The dimensions of the product are 3  2. Example 3-1a

10. Determine whether the product of is defined. If so, state the dimensions of the product. A • B 3  2 4  3 The inner dimensions are not equal, so the matrix product is not defined. Example 3-1b

11. Find RS if Example 3-2d

12. Example 3-4c

13. Find A(B + C) if Substitution Add corresponding elements. Example 3-5f