Answer to Question #230372 in Algebra for moe

Question

Which of the following statements are true with regard to Gauss elimination when solving a system of linear equations? More than one answer may be correct

1. Multiply one row of the augmented matrix by a non-zero constant.
2. Add or subtract a multiple of one row of the augmented matrix to or from another row, while leaving one row unchanged.
3. Interchange two rows of the augmented matrix.
4. The system of equations to be solved must have as many unknowns as the number of equations.