If A is a square matrix and A² = A, then (I + A)² – 3A is equal to:

A square matrix is a matrix with the same number of rows and columns. It has the form of n x n where n is the number of rows and columns. Square matrices are used in various operations such as finding determinants and solving systems of linear equations.

Class 12 Maths Chapter 3 on Determinants covers square arrays of numbers used to solve linear equations. Topics include properties of determinants calculation of 2×2 and 3×3 determinants cofactor expansion adjoint method Cramer’s rule and applications in finding areas of triangles and solving linear systems. Determinants are essential in algebra and geometry.