A matrix is every set of numbers or terms arranged in a rectangular shape, forming rows and columns.
Each number in a matrix is an element. One element is distinguished from another by its position, that is to say, the row and column to which it belongs.
The number of rows and columns of a matrix is called the dimension of a matrix. Thus, a matrix is of dimension: 2x4, 3x2, 2x5,... If the matrix has the same number of rows and columns, is said to be of order: 2, 3, ...
The set of matrices of m rows and n columns is denoted by Amxn or (aij), and any element within the matrix is in row i in column j, for aij.
Two matrices are equal when they have the same dimension and equal elements which occupy the same place in both.