Find the equation of the parabola with directrix y 32 and f
     Find the equation of the parabola with directrix: y = 3/2 and focus: (0, -3/2)  Find the Focus, Vertex, and the equation of the Directrix of the parabola given by the equation:  y^2 = --I2x 
  
  Solution
1) y = 3/2 , focus = ( 0 , -3/2)
equation of parabola is
-6y = x^2
2) y^2 = -12 x
p = -12/ 4 = - 3
Focus : (h + p , k)
h = 0 , k = 0
Focus = (-3, 0)
Vertex = (0, 0 )
Diretrix : x = k - p = 0 - ( -3) = 3
x = 3

