Systems of Equations and Inequalities: Matrices and Determinants

Matrix Basics

A matrix (pl. matrices) is a rectangular array of numbers or values enclosed in a single set of brackets. The dimensions of a matrix are the number of rows and the number of columns. If a matrix has 3 rows and 4 columns, the dimensions are 3 x 4.

The following is a general 2 x 2 matrix.

two rows and two columns written inside a set of brackets, row one has a sub 1 1, a sub 1 2, row two has a sub 2 1, a sub 2 2

Each number or value in a matrix is called an entry.

a11 stands for the entry at position row 1 column 1.
a12 stands for the entry at position row 1 column 2.

You can continue to name the entries in this fashion. This is called the matrix address.