Answer
$\sim\left[\begin{array}{lll}1 & 1 & 1 \\ 1 & 2 & 2\end{array}\right]$
Work Step by Step
Result of a system with $2 \times 3$ coefficient matrix is a line when system has one free variable.
For example:
$\left[\begin{array}{lll}1 & 1 & 1 \\ 0 & 1 & 1\end{array}\right]$
This matrix is in echelon form, so just add first row to second:
$\sim\left[\begin{array}{lll}1 & 1 & 1 \\ 1 & 2 & 2\end{array}\right]$
