Determinants of a matrix

Determinant: the associated algebraic number associated with a matrix

Matrix: an array of numbers set inside of a two brackets

Notations of determinants differ. There are 2 ways to do a determinant. 

How to do a 2x2 matrix determinant

This is quite a simple application of timesing the top left and bottom right numbers then subtracting the multiplication of the bottom left and top right numbers. 

Determinant of 3x3 matrices. 

These are hard yet simple. The easiest way is to take the first 2 columns, copy them, and move them to the end of the matrix. After that take the first 3 diagonals starting at the top left and going down and multiply those numbers in their individual columns. Then add the other 2 columns to the first. after that take the columns going diagonally up from the bottom right and across and multiply those together. Then subtract all three of those columns from the columns of the first three. This will give a person their matrix.