[tex]\begin{gathered} x=-3y+1 \\ -3x-3y=-15 \end{gathered}[/tex]
Substitution
[tex]\begin{gathered} -3(-3y+1)-3y=-15 \\ 9y-3-3y=-15 \\ 9y-3y-3=-15 \\ 6y-3=-15 \\ 6y=-15+3 \\ 6y=-12 \\ y=-\frac{12}{6} \\ y=-2 \end{gathered}[/tex][tex]\begin{gathered} x=-3y+1 \\ x=-3(-2)+1 \\ x=6+1 \\ x=7 \end{gathered}[/tex]
The answer would be x = 7 and y = -2
