Write the Word or Phrase That Best Completes Each Statement $L=\left[\begin{array}{lll}1 & m & n \\ p & q & r\end{array}\right]$

Essay

Write the word or phrase that best completes each statement or answers the question
-Using the matrices $L=\left[\begin{array}{lll}1 & m & n \\ p & q & r\end{array}\right]$ and $O=\left[\begin{array}{lll}0 & 0 & 0 \\ 0 & 0 & 0\end{array}\right]$ , verify that $L+O=L$ .