Given:
[tex]\begin{gathered} -x-3y=-6\ldots\text{ (1)} \\ x+3y=6\ldots\text{ (2)} \end{gathered}[/tex]
Adding equation(1) and equation(2)
[tex]\begin{gathered} -x-3y+x+3y=-6+6 \\ 0=0 \end{gathered}[/tex]
The system has infinitely many solution .
They must satisfy the equation:
[tex]y=\frac{6-x}{3}[/tex]
