So we are asked to find the second derivative (implicitly) of : x^2y^2-6x=7

So far I've been able to find the first derivative no problem.

My first derivative is: -(x*y^2 + 3) / y*x^2

I've verified this against two different online implicit differentiation calculators so I know I'm right to this point.

However I need to take the derivative of this first derivative to reach my goal.

I can not figure it out. Below I'll include two answers that have so far been marked wrong by webassign.net

a) -(y^3*x - 6y) / x(-y^2*x + 3)

b) (x*y^2 + 6) / (x^3*y)