how do i write this equation...

ellipse with the vertices of (6,3) and (6,-3) and a focus at (6,-2)

from your data I can tell that the major axis is parallel to the y-axis and the centre will be (6,0).

a= ?
b= 3
c= 2

for a vertical ellipse a^2 + c^2 = b^2
a^2 + 4 = 9
a^2 = 5

equation :
(x-6)^2 /5 + y^2 /9 = 1