What is a matrix in mathematics?

A matrix in mathematics is defined as a rectangular arrangement of numbers, symbols, or expressions, organized in rows and columns. This structure allows for efficient manipulation and representation of data, making matrices a fundamental concept in various areas such as linear algebra, computer science, and statistics.

For example, you might encounter a matrix used to represent a system of linear equations, where each row corresponds to an equation and each column corresponds to different variables. This organized form of data makes it easier to perform operations such as addition, multiplication, and finding determinants, which are essential in solving systems of equations and performing transformations in higher dimensions.

While other options describe different mathematical concepts or objects, such as geometric shapes, lists, or single values, they do not accurately depict the structured arrangement that characterizes a matrix. This is why the description of a matrix as a rectangular arrangement of numbers or expressions is the most accurate among the given choices.