Are you sure you have read the problem correctly? This matrix has 5 columns but only four rows. The "stair step will reach the bottom" (by which I guess you mean there are no "0" rows) no matter what a is.
Hi,
Given the matrix
A= 1 1 0 1 4
2 0 0 4 7
1 1 1 0 5
1 -3 -1 -10 a
determine the value of a such that, in a row-echelon form of A, the stairstep reaches the bottom.
#The answer is a=1 but I have no idea why is it so???...Thanks in advance for any help you are able to provide...