A matrix is ________ when the number of rows equals the number of columns.
2. For a square matrix, the entries a11, a22, a33, . . . are the ________ ________ entries.
3. A matrix derived from a system of linear equations (each written in standard form with the constant term on the right) is the ________ matrix of the system.
4. A matrix derived from the coefficients of a system of linear equations (but not including the constant terms) is the ________ matrix of the system.
5. Two matrices are ________ when one can be obtained from the other by a sequence of elementary row operations.
6. A matrix in row-echelon form is in ________ ________ ________ when every column that has a leading 1 has zeros in every position above and below its leading 1.