We have the next information
Parabola that opens to the left
Vertex a the origin (0,0)
Focus (-4,0)
then we will have the next form for the equation of the parabola
[tex]y^2=4px[/tex]
where p is -4
[tex]\begin{gathered} y^2=4(-4)x \\ y^2=-16x \\ \end{gathered}[/tex]
therefore if we isolate the x we obtain
[tex]x=-\frac{1}{16}y^2[/tex]
