Question:
If $A=\left(\begin{array}{ccc}2 & 1 & 1 \\ 1 & -2 & -1 \\ 0 & 3 & -5\end{array}\right)$, find $A^{-1}$
Using $A^{-1}$, solve the following system of linear equations:
$2 x+y+z=1$
$x-2 y-z=\frac{3}{2}$
$3 y-5 z=9$
HINT: Here $A=\left(\begin{array}{ccc}2 & 1 & 1 \\ 1 & -2 & -1 \\ 0 & 3 & -5\end{array}\right)$,
$\mathbf{X}=\left(\begin{array}{l}x \\ y \\ z\end{array}\right)$ and $\mathbf{B}=\left(\begin{array}{l}1 \\ 3 / 2 \\ 9\end{array}\right)$
Solution:
