Suppose you’re doing elementary row operations on matrices which have real entries and have 3 rows.
(a) Write down the elementary matrix which correspond to the elementary row operation r3 → r3 + π · r2.
(b) What elementary row operation is performed by left multiplying by the following elementary matrix?
$$ \begin{matrix} 1 &0 &0 \\ −5 &1 &0 \\ 0 &0 &1 \\ \end{matrix} $$
To find (a), would I just do the row operation r3 → r3 + π · r2 on the 3x3 identity matrix?
For (b), any guidance would be helpful.
Thanks!