Given horizontal axis length is larger than the vertical axis length, the standard form of an ellipse is:
[(x-h)/a]^2 + {(y-k)/b]^2 = 1
where (h,k) is center; a and b are the major and minor axis
(h,k) = (0,0) and a=18, b=2
(x/18)^2 + (y/2)^2 = 1 is the standard form equation