If the value of y varies directly with x, means that there is a constant of proportionality
[tex]y=kx[/tex]use that y=-3 when x=1
[tex]\begin{gathered} -3=k\cdot(1) \\ -3=k \end{gathered}[/tex]use k to find y when x=-6
[tex]\begin{gathered} y=-3(-6) \\ y=18 \end{gathered}[/tex]