This document appears to be MATLAB code that performs Gaussian elimination on a matrix D to solve a system of linear equations. The code: 1) Inputs a matrix Z and creates an identity matrix B of the same size to form the augmented matrix D; 2) Performs Gaussian elimination on D by pivoting rows if needed and eliminating variables below the diagonal; 3) Back-substitutes to solve for the vector x; and 4) Displays the output matrix D and solution vector x after running Gaussian elimination.