Question

Which of the following conditions must a matrix satisfy for it to be in a row echelon form.

• A. First non zero element of each row should be greater than 1
• B. First non zero element of each row should be 1.
• C. All zero rows should be on the top.
• D. All non zero rows should be above all zero rows.

Answer 1

Answer: (B), (D)

All non zero rows should be above all zero rows.

The conditions for a matrix to be in row echelon form are

1. All non zero rows should be above all zero rows.
2. $1^{st}$ non zero element of each row should be 1
3. Number of zeros before the $1^{st}$non zero element in $1^{st}$, $2^{nd}$, $3^{rd}$…. rows should be increasing.

Therefore only 2, 4 are correct options.