Question

Part A
Mark the focus of the parabola you are going to create at F(6, 4). Draw a horizontal line that is 6 units below the focus. This line will be the directrix of your parabola. What is the equation of the line?

Answer 1

4-6=-2
eq. of line (directrix) is
y=-2

Answer 2

let P(x,y) be any point on the parabola.
Draw \[PM~ perpendicular~ on~ directrix ~y=2 ~or~ y-2=0\]
then by def. of parabola
PF=PM
\[\sqrt{(x-4)^2+(y-6)^2}=\frac{ |y-2| }{ \sqrt{0^2+1^2} }\]
squaring
\[(x-4)^2+(y-6)^2=(y-2)2\]
simplify and you get the eq. of parabola.