This rule is a way to solve square systems using determinants.
Determinants ditch the brackets and use vertical lines instead. You can only find a determinant for a square matrix. Example:
Entries are the numbers or variables inside the brackets. In the example for the term "Matrix" the entries are 2, 4, -3, 1, -7, and 41.
Variables or constants arranged like a grid in rows and columns that together make up a rectangle. The rows
go across ( "2 4 -3" in the first example below is a row) and the columns
are vertical (in the same example below "2 1" is a column); they're like the columns in the Lincoln Memorial
. Examples: A 2 × 3, a 2 × 2 and a 4 × 1, in that order:
In these, we used basic operations to combine systems of matrices.