5.98 How to do Gaussian elimination on a Matrix?

Given

\[ \left [\begin {array}{cccc}1 & -4 & -3 & -7 \\2 & -1 & 1 & 7 \\1 & 2 & 3 & 11 \end {array}\right ] \]

Find the new form after Gaussian elimination

restart; 
A:=Matrix([[1,-4,-3,-7],[2,-1,1,7],[1,2,3,11]]); 
LinearAlgebra:-GaussianElimination(A);
 

\[ \left [\begin {array}{cccc}1 & -4 & -3 & -7 \\2 & -1 & 1 & 7 \\1 & 2 & 3 & 11 \end {array}\right ] \]