Question 1087427
<pre> This is exactly like the other one I did for you, except
it opens left instead of right.  Hey, you've got to learn this 
stuff, because you have to pass the tests all by yourself.  

{{{(y-k)^2=4p(x-h)}}}

has vertex (h,k), and distance from vertex to both focus
and directrix is |p|.  If p is negative the parabola opens
leftt with the vertical directrix is |p| units right of the 
vertex and the focus is |p| units left of the vertex.  

{{{(y-0)^2=-25(x-0)}}}

has vertex (0,0), and distance from vertex to both focus
and directrix is |-25/4| or 25/4.  Since -25/4 is negative the 
parabola opens left with the vertical directrix 25/4 units  
right of the vertex and the focus is 25/4 left of the vertex.  

So the focus is 25/4 units left of vertex (0,0) which is (-25/4,0),
and the directrix is a vertical line 25/4 units right of the 
vertex (0,0) which is the vertical line x = 25/4

{{{drawing(400,400, -7,7,-7,7,

 graph(400,400, -7,7,-7,7,-sqrt(-25x)),
locate(4.6,4,x=25/4),
 graph(400,400, -7,7,-7,7,sqrt(-25x)),
locate(-7,1.4,(matrix(1,3,-25/4,",",0))),
green(line(25/4,-20,25/4,20)), circle(-25/4,0,.15) )}}}

Edwin</pre>