For 10 points, name this term for a set of numbers arranged in a rectangular box usually offset by brackets.
Gaussian elimination can reduce these mathematical entities into row echelon form. Their addition is commutative, but generally, multiplication of them is not. The determinant can only be found in square ones; and in a two by two one, the determinant can be found using the formula ad-bc. For 10 points, name this term for a set of numbers arranged in a rectangular box usually offset by brackets.
Gaussian elimination can reduce these mathematical entities into row echelon form.
matrix [or matrices]