Find the directrix and focus of parabola

Question

A parabola is given by the equation y2 = -24x.

find the directrix and focus of the parabola

 

Answer 1

y²=-24x

(y-k)²=4p(x-h)

(y-0)²=4(-6)(x-0)

focus=(h+p,k)

focus=(0+[-6],0)

focus=(-6,0)

directrix is x=h-p

directrix is x=0-[-6]

directrix is x=6