6.4. EXERCISES 121

(c)

1 2 3 21 3 2 34 1 5 01 2 1 2

, ( −2.)

2. Find the following determinant by expanding along the first row and second column.

det

 1 2 12 1 32 1 1

3. Find the following determinant by expanding along the first column and third row.

det

 1 2 11 0 12 1 1

4. Find the following determinant by expanding along the second row and first column.

det

 1 2 12 1 32 1 1

5. Compute the determinant by cofactor expansion. Pick the easiest row or column to

use.

det

1 0 0 12 1 1 00 0 0 22 1 3 1

6. Find the determinant using row operations.

det

 1 2 12 3 2−4 1 2

7. Find the determinant using row operations.

det

 2 1 32 4 21 4 −5

8. Find the determinant using row operations.

det

1 2 1 23 1 −2 3−1 0 3 12 3 2 −2

