2x+3y=1 and -3x+y=15 how do you get points (-4,3)

2x+3y=1 and -3x+y=15 how do you get points (-4,3)

$$\begin{array}{rrcl|lrcl}
(1) & 2x+3y &=& 1 \quad & \quad (2)& -3x+y &=& 15 \quad | \quad * 3 \\
& & & \quad & \quad (2)& -9x+3y &=& 45 \\
\hline
\end{array}$\\\\\\$
\small{\text{
$
\begin{array}{lrcl}
(1)-(2): & 2x-(-9x) +3y -3y &=& 1-45 \\
& 11x &=& -44 \\
& \textcolor[rgb]{1,0,0}{x} &\textcolor[rgb]{1,0,0}{=}& \textcolor[rgb]{1,0,0}{-4} \\\\
\hline \\
(1) & 2(-4) + 3y &=& 1 \\
& -8 + 3y &=& 1 \\
& 3y &=& 9 \quad | \quad : 3\\
& \textcolor[rgb]{1,0,0}{ y} &\textcolor[rgb]{1,0,0}{=}& \textcolor[rgb]{1,0,0}{3}
\end{array}
$
}}$$