[tex]x-3y=-7\qquad|-x\\\\-3y=-x-7\qquad|:(-3)\\\\y=\dfrac{x+7}{3}[/tex]
We choose any values of x and calculate the value of y
[tex]for\ x=-4\to y=\dfrac{-4+7}{3}=\dfrac{3}{3}=1\to(-4,\ 1)\\\\for\ x=-1\to y=\dfrac{-1+7}{3}=\dfrac{6}{3}=2\to(-1,\ 2)\\\\for\ x=2\to y=\dfrac{2+7}{3}=\dfrac{9}{3}=3\to(2,\ 3)[/tex]