6. Find the g-inverse of the 3 x 3 matrix A where

$$A = \begin{bmatrix} 3 & 2 & 1 \\ 1 & 1 & -1 \\ 3 & 1 & -1 \end{bmatrix}$$

using the methods presented in each of the Theorems 6.5.1, 6.5.2, 6.5.5, and 6.5.8.