(1/4X^2-4/9Y^2 )/ (1/2X^2-2/3XY)
=(1/2x-2/3y)(1/2x+2/3y) / ((1/2x-2/3y)*1/x)
=(1/2x+1/3y) / 1/x
=x(1/2x+2/3y)
=1/2+2x/3y