Question 619253
Find vertex, focus, and directrix of the parabola.1/2y^2 +18x=0
Given parabola opens leftwards
Its equation: (y-k)^2=-4p(x-h), (h,k)= (x,y) coordinates of vertex 
1/2y^2 +18x=0
1/2y^2 =-18x
y^2=-36x
vertex: (0,0)
axis of symmetry: y=0 or x-axis
4p=36
p=8
focus: (0-p,0)
=(0-8,0)
=(-8,0)
..
Directrix: x=8 (p units to the right of vertex on the axis of symmetry)