3. Find the reduced form \( A_{R} \) of the matrix \( A \), and produce a matrix \( \Omega \) such that \( \Omega A=A_{R} \) \[ A=\left(\begin{array}{ccc} 3 & 2 & -12 \\ 1 & -1 & 1 \\ 4 & 1 & -11 \end