Chapter 2.5, Problem 3P

Explanation of Solution

Inverse of the given matrix:

Consider the given matrix,

$A=\left[\begin{array}{l}101\\ 111\\ 212\end{array}\right]$

Suppose that the inverse of the given matrix is as follows:

$A^{-1}=\left[\begin{array}{l}efg\\ hij\\ klm\end{array}\right]$

Applying Gauss Jordan method,

Replacing row 2 by (row 2 – row 1), the following matrix is obtained,

$[\begin{array}{l}101\\ 010\\ \end{array}$