I am real confused on determants. There is a couple examples below and if someone could show me how this is done that would be great.

Find the determinant for this matrix:

example 1)

2 9 -5 3 9

3 1 5 -3 1

0 -4 1 2 -4

8 5 6 9 5

3 -2 -1 -3 -2

example 2)

3 0 0 0

1 -2 0 0

4 2 -1 0

3 7 2 4