I heard from multiple sources that to obtain the rank of a matrix A, you must first do row reduction to get the row reduced echelon form of matrix A and count the number of non zero rows.
But then there are other sources that say i must use row reduction to get matrix A to ROW ECHELON FORM, and not row reduced echelon form.
So which is it? should i transform matrix A to row echelon form or row reduced echelon form to find the rank?