Determine whether the following matrices are in row echelon form (but not reduced row echelon form), reduced row echelon form, or not in row echelon form. (1)[1, 0,0],[0,1,0],[0,0,0](2)[-4,8,4,-7,-2], [0,-6,1,1,1], [0,0,1,0,3],[0,0,0,1,0](3)[7,0,1],[0,6,0](4)[1,0,0,4],[0,0,0,0],[0,1,0,-6]

Sure, let's analyze each matrix one by one:

(1) [1, 0,0],[0,1,0],[0,0,0] This matrix is in reduced row echelon form. Each leading entry is 1 and is the only non-zero entry in its column. Also, all zero rows are at the bottom.

(2) [-4,8,4,-7,-2], [0,-6,1,1,1], [0,0,1,0,3],[0,0,0,1,0] This matrix is not in row echelon form. The leading entry of each row should be 1, but here in the first row, it is -4 and in the second row, it is -6.

(3) [7,0,1],[0,6,0] This matrix is not in row echelon form. The leading entry of each row should be 1, but here in the first row, it is 7 and in the second row, it is 6.

(4) [1,0,0,4],[0,0,0,0],[0,1,0,-6] This matrix is not in row echelon form. The leading entry of each nonzero row should occur to the right of the leading entry of the previous row. But in the third row, the leading entry 1 is not to the right of the leading entry of the second row. Also, all zero rows should be at the bottom, but here the second row is a zero row.