6. For each matrix given below, use the inversion algorithm to find its inverse, if possible. A=\left[\begin{array}{rrr} 0 & 0 & -1 \\ 0 & -1 & -1 \\ -1

& -1 & 0 \end{array}\right] \quad B=\left[\begin{array}{cccc} 1 & -1 & 0 & 0 \\ 3 & -4 & 0 & 0 \\ 0 & 0 & 1 & 3 \\ 0 & 0 & -1 & -4 \end{array}\right]