## Elementary Linear Algebra 7th Edition

$$E=\left[\begin{array}{rrr}{1} & {0} & {1} \\ {0} & {1} & {0} \\ {0} & {0} & {1}\end{array}\right].$$
The matrix $$E=\left[\begin{array}{rrr}{1} & {0} & {1} \\ {0} & {1} & {0} \\ {0} & {0} & {1}\end{array}\right].$$ is elementray and satisfies $$EA=\left[\begin{array}{rrr}{1} & {0} & {1} \\ {0} & {1} & {0} \\ {0} & {0} & {1}\end{array}\right]\left[\begin{array}{rrr}{1} & {2} & {-3} \\ {0} & {1} & {2} \\ {-1} & {2} & {0}\end{array}\right]=\left[\begin{array}{rrr}{0} & {4} & {-3} \\ {0} & {1} & {2} \\ {-1} & {2} & {0}\end{array}\right]=C.$$