Linear AlgebraEasyRow Reduction & Rank

Row Reduction & Rank · Easy problem

Elimination without row exchanges writes $A = LU$ for

A = \begin{pmatrix} 2 & 1 & 1 \\ 4 & 3 & 3 \\ -6 & 1 & 2 \end{pmatrix},

where $L$ is lower triangular with $1$ s on its diagonal. What is the entry $\ell_{31}$ of $L$ ?