연립방정식 $\begin{pmatrix*}[r] 1 & 0 & 0 \\ 1 & 1 & 0 \\ 1 & 1 & 1 \end{pmatrix*} ^{{-1}} \begin{pmatrix*}[r] 1 & -1 & 0 \\ 0 & 1 & -1 \\ 0 & 0 & 1 \end{pmatrix*} \begin{pmatrix*}[r] x \\ y \\ z \end{pmatrix*} = \begin{pmatrix*}[r] 2 \\ -1 \\ 3 \end{pmatrix*}$ 의 해 $\left (x, y, z \right)$ 는?

• ①$\left (4, 1, 2 \right)$
• ②$\left (2, 1, 4 \right)$
• ③$\left (7, 5, 4 \right)$
• ④$\left (4, 5, 7 \right)$