Below are matrices.
A= 4 5 2 1
0 1 8 2
0 15 2 1
** A is a 3x4 matrix.
L = 1 0 0
0 1 0
0 k 1
A = LU
If U is found by exactly 1 row-operation to A, what is the value of k?
I do not think that your question makes sense. What is U?