y^2 = (a^2 x) / (2a - x )

Find points of inflexion and sketch the curve.

By implicitly differentiating Ive got a value for dy/dx

= 2a^3 / (2a-x)^2 ( 2y)

However, I do not know how to do from here. Do I implicitly differentiate again or ... and how do i do that?