Um, I was asking about *determinants.* Unless determinants are the same as dimensions, but I don't think that your post found the determinant of either matrix.
Could someone please help me with determinants?
If two columns or rows of a matrix nxn are linearly dependent, then the matrix is not of rank n.
For the first one, the 4th column is 11 times the 1st one.
For the second one, it is obvious that with the null column, the matrix is not of rank n.
Edit : excuse me, I confused myself between rank and dimension