=============================================

300C,

standard from isx = a [( y-k)^2] + h

If a<0, it opens to left horizontally.

where,Focus point is { [ h+ (1/4a)], k }

Rewrite your question to standard from and get

x = (- 1/4) [ ( y-0)^2 ] + 0

where you seea = -1/4, k=0, h=0

Now Focust point is([ h+ (1/4a)] ,0)

Solve [ h+ 1/(4a) ] by substitue a = -1/4 and get -1

so Focusto points =( -1, 0 )