The slope-intercept form of a line is given by:
[tex]\begin{gathered} y=mx+b \\ where\colon \\ m=slope \\ b=y-in_{}tercept \end{gathered}[/tex]So:
[tex]\begin{gathered} 3x+6y=6 \\ solve_{\text{ }}for_{\text{ }}y\colon \\ 6y=6-3x \\ y=\frac{6-3x}{6} \\ y=-\frac{1}{2}x+1 \end{gathered}[/tex]