determinant of non square matrix

ahmednet24

in fact I try to understand the paper that I mention to it,I don't know how they find the determinant of a matrix of size 2x3, My problem I have to find the determinant of a matrix 3x15.

ahmednet24	in fact I try to understand the paper that I mention to it,I don't know how they find the determinant of a matrix of size 2x3, My problem I have to find the determinant of a matrix 3x15.