Row and column matrix operations

[Shackleford]

Are you allowed to mix and match row and column operations? For (a), using only row operations, I cannot get the matrix into the form they want. Could I swap a few of the columns around to do so?

For (b), I got it into the form they want. The rank of the matrix is 2 because I have I₂ there.

http://i111.photobucket.com/albums/n149/camarolt4z28/IMG_20110620_195851.jpg

http://i111.photobucket.com/albums/n149/camarolt4z28/IMG_20110620_210944.jpg

http://i111.photobucket.com/albums/n149/camarolt4z28/IMG_20110620_195802.jpg

 

[shelovesmath]

You can do column and row operations when finding the determinant.